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M
Automobile
Starting and Lighting
A Non - Technical Elxplanation of the
Construction, Upkeep and Principles
of Operation of the Electrical
Equipment of Automobiles
HAROLD P: manly
ILLUSTRATED
CHICAGO
FREDERICK J. DRAKE & CO.
Publishers
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; .TJ ^
I .' Copyright, 1918 & 1916,
By
FREDERICK J. DRAKE & CO.
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PREFACE
\ ** Automobile Starting and Lighting" has been
^ written to give a working knowledge of the construc-
tion and action of the various parts of electrical
^ equipment, together with a necessary understanding
^, of the principles that govern their operation. The
<^ ^ necessity for such a work is evident in that more than
^ ninety-eight per cent of all cars now produced are
electrically started and lighted.
Detailed explanation is given of all types of con-
I struction at present in use or that have been adopted
\^ in former installations, thus allowing the user to apply
r^ the information to future developments as well as to
^ all those now found. By treating the subject accord-
ing to the several units entering into all constructions,
the entire field has been covered without the neces-
^ sity of too brief explanation or such repetition as
) would be called for by other methods. The particular
^ applications found in the well-known makes of appa-
i^ ratus have been outlined in one portion of the book.
The attention of the practically inclined user is
4 called to the chapter on storage batteries, to the
i chapter describing the action of regulating and cut-
^ out devices, to the chapter on Troubles and Remedies,
^ and to the last chapter, in which has been explained
^ the meaning of two hundred of the words aiid terms
generally used in starting, lighting and ignition work,
and in the application of electrical science found in
this field.
THE AUTHOR.
5
. i -'On' > .' •
/ Digitized by VjOOQIC
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CONTENTS
CHAPTER I
Elsotbio Lighting and Engine-Startino Equipment. ... 9
CHAPTER II
Lighting Dynamos and Starting Motors 34
CHAPTER III
Storage Batteries 70
CHAPTER rv
Lamps and Wiring 92
CHAPTER V
Controlling Devices, Cut-Outs and Regxtlators 120
CHAPTER VI
Drive Methods and Starting Switches 177
CHAPTER VII
Indicating Devices and Trouble Location 211
CHAPTER VIII
Makes and Types op Equipment 241
CHAPTER IX
Electrical Words and Terms 269
Index 295
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AUTOMOBILE STARTING
AND LIGHTING
CHAPTER I
ELECTEIC LIGHTING AND ENGINE-STARTING
EQUIPMENT
The fundamental principles employed in all of the
various makes of automobile electrical equipment are
the same regardless of the particular application
chosen by the designers and builders. All systems
must provide parts which accomplish certain results
essential to the operation of the system as a whole.
In some cases a single part may perform two or
more functions, in other cases separate parts wiU be
provided for each function, while in still other cases
some of the parts may apparently be absent. Never-
theless, every successful electrical installation must
cause the same actions to take place, and parts must
be provided that will bring about the effects necessary
for continued operation.
It is first of aU necessary to cause a flow of elec-
tric current, and this is done by the dynamo, or gen-
erator, operated by the gasoline engine. A certain
amount of power is required to run the dynamo, and
this power is taken through gears, chains or belts be-
tween the engine and dynamo or by mounting the dy-
namo on the engine crankshaft. The dynamo may be
9
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10 STARTING AND LIGHTING
defined as the mechanism that changes the mechani-
cal power received from the engine into electric cur-
rent.
It is evident that the engine cannot always be
running when current is required, inasmuch as it is
necessary to light the lamps under this condition and
to start the engine from rest. It is, therefore, neces-
sary to accumulate and store the surplus energy
that is produced during the time the engine runs
under its own power, and this is accomplished by the
storage battery which is a vital part of every elec-
trical equipment.
Having a source of current and a means of retain-
ing a part of the energy until it is needed, it remains
to attach the parts that consume current in lighting,
starting, ignition and control of the automobile.
These parts include the various lamps, an electric
motor for cranking the engine, and in many cases the
parts for ignition, gear shifting, carburetor heating
and the many electrical accessories which are found
in use.
Thus, the four essentials of the electric system are
dynamo, battery, lights and starting motor. In order
to allow the operator of the car to use these parts,
and to cause them to perform their duties properly
and without danger to themselves, certain controlling
and regulating devices are necessary.
For convenience in further explanation, the elec-
trical apparatus of the car wiU be divided into three
principal parts (Figure 1), the charging system, the
lighting system, and the starting system. The charg-
ing system will include the dynamo, the battery, and
all the parts required for their operation and use.
The lighting system will include the lamps and their
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ELECTRIC LIGHTING AND ENGINE STARTING
11
wiring^ also the parts needed for their control. The
starting system will include the starting motor, the
starting switch and the necessary wiring.
In order to prevent confusion, the following usages
have been adopted and will be followed throughout
this work. While both words refer to the same instru-
ment, the word ** dynamo" will be used in preference
to ** generator'* whenever the dynamo-electric ma-
chine is used to cause a flow of current. The word
Battery JT ^
/— X '-'^"* J—\
Figure 1. — Connections for Charging, Lighting and Starting Systems.
** motor" will refer to the electric starting motor and
not to the automobile engine. The combination of
dynamo and motor in one unit will be called a ^^mo-
tor-dynamo." For an explanation of the meaning
of electrical words and terms used in starting and
lighting, see Chapter IX.
CHARGING SYSTEM
Dynamo, — The dynamo consists of a revolving
element, operating in connection with a stationary
element. The rotation of one of these parts with
reference to the other generates a flow of electric
current in one of them, called the armature, and
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12
STARTING AND LIGHTING
the current then passes from the armature out of the
dynamo to the battery and other electrical parts.
The second element is called the field magnet, and
provides the necessary magnetism.
The usual construction, Figure 2, makes the arma-
ture the rotating element, and the most common form
of armature is built by mounting on a shaft a suffl-
Figure 2. — ^Lines of Force Passing Through Dynamo Armature.
cient number of soft iron discs to make a cylinder,
or else a cylindrical piece of soft iron is used in one
piece. This part is called the armature core. Run-
ning lengthwise of the core are a number of grooves
or slots, these slots being of sufficient width and depth
to ^low a quantity of insulated wire to be wound on
the core and in the slots. The coils formed by this
wire are called the armature windings, and it is in
these windings that the current flow is first generated.
Various forms are adopted for the field magnet,
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ELECTRIC LIGHTING AND ENGINE STARTING
13
the shape depending on the size and mounting that
will be required for the particular machine being
designed. If a single magnet is used, that is, a magnet
having but two ends, these ends are placed in such
a position that they are at opposite sides of the arma-
ture core and the magnetism that passes from one
end to the other must therefore pass across and
through the armature core. The ends of the magnet
are curved to bring them close to the armature, and
the cylindrical passage between them, in which the
armature rotates, is called the armature tunnel.
Figure 3. — Two-Pole, Four-Pole and Six-Pole Electric Machines.
Should the magnets be formed with four or six
ends, as is often the case, the ends are placed so that
they form pairs on opposite sides of the armature
and are directly across from each other. The machine
is then called a four-pole or six-pole dynamo (Fig-
ure 3), depending on whether there are four or six
magnet ends placed around the armature.
The magnets that produce the field are made from
soft iron, and the soft iron, called the magnet core,
is surrounded with a coil of insulated wire. When a
flow of current passes through this wire, the soft iron
becomes a magnet, this type being known as an elec-
tro-magnet, as differing from a permanent magnet,
which is made from hardened steel. The coil of wire
around the magnet core is called the field winding,
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14 STARTING AND LIGHTING
and the current that passes through this winding to
make the core magnetic is secured by taking a part
of the current generated in the armature.
As the armature rotates between the field magnet
poles, the current caused to flow through each one
of the armature coils travels in one direction through
the wire while the armature and coil make a half
revolution, and then, on the next half revolution,
the current is caused to pass in the opposite direction
through the winding. A current that reverses its
direction of flow in this way is called an alternating
current, and is not suitable for battery charging pur-
poses because of the fact that the reversal of flow
would take out as much current as it would put into
the battery.
In order to change this alternating current into a
flow that always travels through a wire in one direc-
tion, the commutator is used. The current having a
continuous direction of travel is called direct current,
and. is the only form suitable for battery charging.
The commutator consists of a number of copper
bars arranged in a circle around one end of the
armature shaft and fastened to the shaft so that they
turn with it. These bars are separated from each
other by some material that will not carry electric
current ; in other words, are insulated from each other.
Each pair of copper bars is fastened to an armature
winding coil that rests in one pair of slots, and the
other bars are fastened to the other coils of wire that
form the armature. This construction makes it nec-
essary to have double the number of commutator
bars that there are armature windings, each pair of
bars forming the two ends of one coil on the armature.
Because of the fact that a flow of current is gen-
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ELECTRIC LIGHTING AND ENGINE STARTING
15
erated in an armature coil while it is passing across
one of the magnet poles, one electrical impulse is
generated in each direction by a two-pole machine,
as already mentioned. One complete revolution of
the armature, Figures 4 and 5, will cause both sides
of the coil, which means the whole coil, to pass first
across the end of one pole of the magnet, then across
the end of the other pole. This action will send an
impulse to the commutator bars first in one direction,
then in the other.
Two brushes, made from some material that carries
electricity with ease, are placed so that they rest
Figure 4. — Armature C
Passing Negative Pole.
CoU
Figure 5. — ^Armature CoU
Passing Positive Pole.
against the surface of the commutator bars and at
opposite points on the commutator surface. The
brushes are therefore in contact with opposite bars
at the same time, and with the two ends of the arma-
ture coil. Any flow of electric current generated in
the armature winding will pass into these brushes.
Now, bearing in mind the fact that the current
reverses each half revolution, and also the fact that
the commutator bar in contact with one brush at one
position will ha^e changed to the other brush when a
hialf revolution has been made, it will be seen that the
current will always be given to the brushes in the
same direction. This is true because, while the direc-
tion of flow has reversed, the position of the commu-
tator bars with reference to the brushes has also
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16 STARTING AND LIGHTING
reversed, and as far as the brushes are concerned, the
flow continues in the same way.
Should the dynamo be a four- or six-pole unit, the
reversal of current will take place four or six times
in a revolution, and it is customary to provide four
or six brushes, half of the total number in any case
taking the. current flowing in one direction, while the
remaining brushes take the current flowing in the
opposite direction.
From the brushes, wires and connections lead to
the battery, lamps and other current-consuming de-
vices, and in most cases to the field. magnet windings
also. The method of leading part of the generated
current around the field magnets is one of the impor-
tant considerations in dynamo design, and will be
considered in the next chapter.
Current Measuremerd. — Electricity is not a mate-
rial thing and cannot be measured according to the
usual standards of weight or dimensions. It can
only be measured by its effects that are produced in
various ways. The two principal values of electricity
that are generally useful in this work are pressure,
expressed in volts, and rate of fiow, expressed in
amperes.
Electricity passes through conductors, such as wires
and all other metallic things, because of the pressure,
or voltage, and the flow sent through the conductor
by this pressure is measured as amperage. The actual
flow depends on the pressure being exerted and the
resistance of the wire or other conductor to the pass-
age of the current. If the voltage remains at a
constant point, the flow sent through the conductor
will be in proportion to the resistance ; more flow
passing as the resistance becomes less, and less flow
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ELECTRIC LIGHTING AND ENGINE STARTING
17
passing as the resistance increases. Should the re-
sistance remain the same, an increase of voltage will
cause an increased flow, while a decrease in voltage
will allow the flow to become less.
The resistance of a conductor depends on its size
or cross section, the resistance becoming less as the
size increases. Resistance also depends on the length
of the conductor through which the electricity must
pass, the resistance increasing in direct proportion
to increase in length. Other things affecting the
resistance are the material of the conductor, some
Electricity
Unit of
Water
Volt
Ampere
Watt
Pressure
Flow
Power
Pounds to Square Inch
Gallons per Minute
Horsepower
Figure 6. — Electrical and Hydraulic Units Compared.
metals being much better conductors than others, and
also the temperature, high temperatures generally
causing the resistance to increase.
It should be clearly understood that voltage- mea-
sures only the pressure and does not indicate any
particular quantity or volume of electricity. Voltage
corresponds to pounds to the square inch in hydraulic
work and similarly indicates only the pressure that
is available when a flow takes place.
On the other hand, amperage measures only the
rate at which the current passes a given point, and
unless the amount of time during which this flow
continues is known, the amperage does not indicate
the quantity of current that has passed. Amperage
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18 STARTING AND LIGHTING
may be compared to the measurement of water flow
in gallons per minute, when, unless the number of
minutes is known, the quantity of water cannot be
calculated. (See Figure 6.)
The useful work that electric current can perform
depends on the pressure, or voltage, available, and
also on the rate of flow, or amperage. A current of
one ampere having a pressure of ten volts will do
exactly the same work that a current of ten amperes
at one volt will do. Any other combination of volts
and amperes which multiplied together will, give ten
will likewise do an equal amount of work. The work
that a current will do is measured in watts, one watt
being the power furnished by a flow of one ampere
at a pressure of one volt. Any number of amperes
multiplied by the number of volts pressure will give
the number of watts. Thus, a lamp through which
a current of two amperes is flowing under a pressure
of six volts is consuming twelve watts in electrical
power. An electric starting motor through which one
hundred amperes is flowing at six volts is consuming
six hundred watts in electrical power. Seven hun-
dred and forty-six watts in electrical power is the
equal of one mechanical horsepower.
Before leaving the subject of electrical measure-
ments^ it should be explained that the resistance of
any mate;rial, such as a conductor, is measured in
ohms, and the relation between the arbitrary units,
volts, ohms and amperes, may be explained as follows :
A volt is the pressure required to force one ampere
flow against a resistance of one ohm.
An ampere is the flow caused by an electrical pres-
sure of one volt acting against a resistance of one
ohm.
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ELECTRIC LIGHTING AND ENGINE STARTING
19
An ohm is the resistance that will allow a flow of
one ampere to pass under a pressure of one volt.
The practical expression of ''Ohm's Law," one of
the most useful rules in electrical work, is as follows:
The voltage is found by multiplying the amperage
by the resistance.
The amperage is found by dividing the voltage by
the resistance.
Figure 7. — Relative Pump Flow at Low and High Speed.
The resistance is found by dividing the voltage by
the amperage.
It will thus be seen that, knowing any two of the
above values, the third may easily be found.
Dynamo Regulation. — ^It is often of assistance in
imderstanding electrical action to compare it to the
action of water. The dynamo may be compared to a
water pump, and the flow of electric current from the
dynamo may be compared to the flow of water from
a pump. In either case, the pressure increases with
increase of speed and tiie higher pressure causes a
greater flow. As the speed of a water pump increases,
the water pressure in pounds to the square inch
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20 STARTING AND LIGHTING
increases, and the flow in gallons per minute then
increases. (See Figure 7.) With increase of dynamo
speed, the pressure, measured in volts, and the flow,
measured in amperes, both increase in proportion.
Just as uncontrolled increase in water pressure and
flow might cause damage, so will unchecked increase
in voltage and amperage result in damage to the elec-
trical parts. Excessive amperage, or flow of current,
would damage the storage battery and the dynamo
itself, while an undue rise in voltage, or pressure, will
damage dynamo, battery and lamps.
In Order to prevent such damage, various methods
have been adopted for controlling the dynamo output.
A suitable operating voltage is selected when the
equipment is designed, this voltage usually being six,
eight, twelve or eighteen, and the design is carried out
in such a way that this voltage is maintained at all
times without considerable increase or decrease.
The flow allowed from the dynamo to the storage
battery should be proportioned to the size of the bat-
tery, and the size of the battery is in turn suited to
the current consumption of the car's equipment.
Control of the dynamo output, that is, its voltage and
amperage, will be designated by the word ** regula-
tion."
Cut-Out, — ^Following the analogy between electric-
ity and water, compare the storage battery to a tank
into which a pump, the dynamo, forces water from a
lower level. It will be understood that the pressure
at the pump must be higher than the pressure at the
tank in order that a flow may take place from pump
to tank. Similarly, the voltage of the dynamo must
be greater than the voltage of the battery in order
that current may flow from dynamo to battery. Just
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ELECTRIC LIGHTING AND ENGINE STARTING 21
as long as the dynamo voltage remains above that of
the battery, the flow will continue and the battery will
receive a charge. When, however, the dynamo volt-
age falls below that of the battery, as it will when the
dynamo is idle or running at very low speed, then
the battery pressure or voltage will be greater than
that of the dynamo, and if the two units remain con-
nected through the wiring, there will be a reverse
flow from battery to dynamo. This reverse flow, if
allowed to continue, will rapidly withdraw the current
from the battery. To prevent such a useless and
damaging battery discharge, one of several methods
is adopted whereby the dynamo is disconnected from
the battery when the dynamo voltage is too low io
cause a flow of current to the battery. One method
makes use of an automatic switch that operates accord-
ing to the voltage of the dynamo, this switch acting
to disconnect the dynamo and battery when the
dynamo voltage falls below a certain limit and to
establish the connection again when the voltage rises
to a point that allows of battery charging. This
switch may operate electrically or by centrifugal force,
either type being called a reverse current cut-out, or
simply a cut-out. A large majority of all cars use
the electromagnetic form.
The dynamo is not always disconnected automat-
ically in one of the ways described, but may be dis-
connected by a switch operated by the person driving
the car. This type of switch is interconnected with
the ignition or starting switch in such a way that the
dynamo and battery will be disconnected whenever
the gasoline engine is idle, or running at low speeds.
The dynamo speed with the engine running at the
usual rate is sufficient to produce a charging voltage.
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STARTING AND LIGHTING
This form of switch is often called a hand-operated
cut-out.
In many cases the automatic cut-out is combined,
or is carried in the same case, with the device for
regulating the dynamo output. In such a design the
combination is called a '* controller." This practice
is often followed when the regulating device is a
separate instrument, complete in itself, but apart
from the dynamo. Many systems are designed in such
Mud t9MM t» htltf Para niblMr Jar
MdlM««t fr«n plattt
Figure 8. — Section Showing Parts of Storage Battery.
a way that regulation of output is accomplished within
the dynamo and by parts of the dynamo. This
internal method is called ** inherent regulation."
Various locations are used for the controller or
the separate cut-out. These units may be carried
inside of the dynamo case or mounted on the outside
of the case. They may be on the engine side or the
driver's side of the dashboard. They may be placed
under th3 driver's seat or, in some cases, under the
floor boards. Other designs locate these units with
the starting switch, lighting switch or other instru-
ments.
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ELECTRIC LIGHTING AND ENGINE STARTING 23
Battery. — ^Although the battery, Figure 8, has been
classed as a part of the charging system, it also forms
an essential part of both lighting and starting sys-
tems because of the fact that it furnishes th^ current
with which these parts operate. Being a part of each
of the three principal divisions makes the storage
battery the center of the whole electrical equipment
and of the greatest importance.
With the exception of the battery, all units of the
starting and lighting equipment operate mechanically
or electrically. The battery is electro-chemical in
action, an^ does not store electricity in the form of
current. Electric current generated by the dynamo
flows through the battery and in doing so causes cer-
tain chemical changes to take place in the elements of
which tfie battery is composed. This action is known
as ** charging," and after the battery has been
charged, the chemical composition of the elements
differs from what it originally was.
After the battery has been chained, it is capable of
causing a flow of current through conductors attached
to it. In causing this flow the battery elements again
go through k chemical change. When the action
within the battery has progressed to a point at which
the elements have returned to their discharged con-
dition, the battery can cause no further flow of cur-
rent. A new flow sent through the battery by the
dynamo will restore the battery elements to their
charged state, and connecting the outside circuits to
the battery will allow the discharge which ends with
a return to the chemical condition called '* dis-
charged."
This fundamental difference between the battery,
which is a chemical unit, and all others, which are
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24 . STARTING AND LIGHTING
electrical or mechanical, causes a large part of the
trouble that results from lack of care on the part of
the user.
Indicating Devices. — ^It is desirable for many rea-
sons to know whether or not the battery is being
charged, and also to know the rate of charge or dis-
charge at any time. It is not possible to measure
directly the amount of current flow that a battery is
capable of delivering, starting with a given time;
that is to say, the "charge" remaining in the battery
cannot be measured. It is, however, possible to make
tests which will give a close approximation of the
condition of charge by testing the liquid contained in
the battery. A less reliable indication is the voltage
of the battery while undergoing charge. The voltage
rises and falls with increase or decrease of current
flow that may still be secured from the battery, and
this voltage may be measured by an instrument called
a voltmeter when electrically connected to the bat-
tery.
Four methods are in use which show directly when
current is being sent from the dynamo to the battery
or lamps. The most satisfactory method, from the
standpoint of accurate information on the exact con-
ditions obtaining at any given time, is by the use of
an ammeter. This instrument, placed in the electrical
circuit, shows the direction of flow and also the
amperage passing. It may be so placed that the flow
either into or out of the battery is indicated at the
time of reading.
Other instruments, called ''indicators,*' are used
for purposes similar to those of the ammeter, the
indicator showing whether the battery is being
charged, discharged or held without flow either way.
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ELECTRIC LIGHTING AND ENGINE STARTING 25
The exact flow in amperes is not measared by an
indicator.
A third method consists of employing a visible
marker or target attached to the automatic cut-out
switch, or to an electromagnet in the charging circuit,
the target being fitted in such a way that the driver
can teU whether or not the dynamo is delivering a
flow of current. Such a target does not indicate
whether the current flow is passing into the battery
or to the lamps, and this method is therefore of value
only for checking the dynamo action.
A fourth method makes use of a lamp called a
''pilot lamp,*' this lamp lighting whenever the dynamo
is connected to the charging circuit by the cut-out,
and remaining dark whenever the cut-out is open and
the dynamo disconnected from the circuits. The pilot
performs the same function as the target mentioned
in the preceding paragraph.
LIGHTING SYSTEM
Lamp Bvlbs. — The incandescent lamps used in auto-
mobile lighting are formed by inserting a strand or
filament of tungsten or carbon in a glass bulb from
^ which all but a small percentage of the air has been
exhausted. Another type of bulb replaces the air
with nitrogen gas, this form of bulb giving a slightly
greater volume of light for the current consumed
than the vacuum type.
All bulbs are rated according to the voltage with
which they are designed to operate and by the number
of amperes or watts used when the proper voltage is
present. Rating is also given in the candlepower
developed when the bulb is consuming the rated am-
perage at the normal voltage.
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26
STARTING AND LIGHTING
The candlepowers in use vary from one to forty,
and the voltages from three and one-half to twenty-
one, according to the equipment of the car. The
eandlepower and voltage do not necessarily bear a
definite relation to the size of the ^ass bulb enclosing
the filament. Various standard sizes of bulb are in
use, and with a lamp case and reflector designed or
focused for a certain size, the use of this size should
Figure 9. — Bayonet or "Bdlswan'* Lamp Base Construction.
be adhered to unless the focusing arrangements allow
of a proper setting for a different bulb.
Three forms of bulb base and socket are in use.
The type most commonly found is the **Ediswan''
or '* bayonet" type (Figure 9). This base is cylin-
drical in form and has two small pins attached to
opposite sides of the round portion of the base. The
bulb fits loosely into a hollow cylindrical socket, and
the pins on the base slide down into lengthwise slots
cut in the sides of the socket. At the bottom of the
socket these slots turn at right angles and extend for
a short distance around the socket, ending in a notch
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, ELECTRIC LIGHTING AND ENGINE STARTING - 27
designed to catch the pins on the base. Springs placed
in the bottom of the socket hold the pins on the base
tight in the notches. Current is carried from the
socket into the bulb through <;ontacts formed by
springs or plungers. These plungers are depressed
when the bulb is put into the socket and form the con-
ductors in most cases.
In the ''double contact'* tj^e of Ediswan base and
socket two plungers are provided which make contact
with two metallic points on the bottom of the base.
One contact carries one side of the electric circuit,
while the remaining contact carries the other side.
The ''single contact'' base has but one plunger and
but one point on the bottom of the base. This contact
carries one side of the circuit, while the other side
of the circuit is carried through the metal that forms
the socket cylinder and the housing for the bulb base,
A third type, of the screw form, is seldom met with
except in interior body wiring. The large size of
screw base is called "candelabra," while a smaller
size is called "miniature."
Wiring and Switches, — In making the necess?,ry
connections on the car, the dynamo is connected to the
battery for chargixig purposes. All of the remaining
principal divisions are also connected to the battery
so that they may secure their supply of current.
This means that all of the current-consuming units
are connected to the dynamo and battery, the inter-
connection being made at the battery terminals or
battery wires. Current from the dynamo may there-
fore pass into the battery or may go to the lamps;
the flow being into the battery with all lamps off or
with such a number of lamps lighted that do not
require all of the current being generated by the
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28
STARTING AND LIGHTING
djniamo. If sufficient lamps are lighted to take all
of the current generated by the dynamo, none will
be left to pass into the battery. If so many lamps are
lighted that they take more current than the dynamo
generates, the battery will be drawn upon for the
balance required. If the lamps are lighted with the
Charge
Batterji
-^Uawp* J
OLscharge
( OjfMune
Bat'tery
Lamps 1
Floating
Battery
Lamps I
Figure 10. — Current Flow Between Battery, Dynamo and Lamps.
Top : Dynamo Running, Lamps Off. Center : Dynamo Idle, Lamps
On. Bottom: Dynamo Running, Lamps On.
dynamo idle, all of the current required will be taken
from the battery. (See Figure 10.)
Three principal methods of lamp wiring are in
use; the one- wire or ground-return method, the two-
wire method, and the three-wire method.
The two-wire was used first. By this method each
side of each lamp is connected directly to the battery
through conductors to form a complete circuit. That
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ELECTRIC LIGHTING AND ENGINE STARTING 29
is, one side of the lamp is connected to the positive
side of the battery while the remaining side of the
lamp is connected to the negative side of the battery,
both sides of the circuits being completed through
copper wire and the necessary switches and fittings.
The one-wire method is a more recent develop-
ment, but has gained rapidly in number of users since
its first introduction. This method utilizes the frame
and other metal parts of the car to complete one side
of the circuit, this being possible because of the fact
that all metals are excellent conductors. Each wire
and each circuit that is connected to the frame or
metal parts is said to be ** grounded," and the metal
parts are referred to as ** ground."
The circuits for a one-wire, or ground-return, sys-
tem are completed as follows: From one side of the
battery, either the positive or negative terminal, a
connection is made to the frame of the car, thus
grounding one side of all circuits. From the remain-
ing battery terminal wires are run to the lighting
switches, to the dynamo and to the other electrical
units that must have connection with the battery.
These wires from the ungrounded side of the battery
are led to one side of each of the lamps and other
units, and the remaining side of each of these units
is then connected to the frame of the car or to other
metal parts in contact with the frame. These ground-
ing connections from the electrical units often require
that, short lengths of wire be used, but the length of
wire used is less by a large percentage than the length
required with the two-wire system.
Each system of wiring has certain advantages of
its own, also disadvantages. Each system has its ad-
vocates, and the arguments put forth are many for
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RO STARTING AND LIGHTING
each side of the question. The principal advantage
claimed for the single-wire system is the comparative
ease of insulating the parts. The size of all parts is
necessarily small, and it is apparent that when the
whole available space can be uiied for insulating one
conductor, the problem is simpler. The principal
advantage of the two-wire system is claimed to be the
comparatively less danger of short circuits because
of the fact that it is pecessary to break the insulation
on both positive and negative sides of the circuit
before an improper flow can take place from one side
of the battery to the other.
The three-wire system may be an adaptation of
either the one- or two-wire system. The three-wire
method makes it possible to use lamps of two different
voltages on the same car and from one battery. The
battery is divided into two parts of such size that
one part gives one voltage desired, while the whole
battery, or the remaining part, gives another voltage
higher than the first. One of the three wires is called
the '* neutral" wire, and if a connection is made be-
tween this neutral wire and one of the others, one of
the voltages is secured, while a connection between the
neutral wire and the third wire will give the second
voltage. Another three-wire system will give the same
voltage between the neutral wire and either of the
others, while a higher voltage may be obtained by mak-
ing a connection between the two outside wires, omit-
ting the neutral wire altogether.
The advantage of a three-wire system is in the
smaller amperage that must be carried through the
wires to do an equal amount of work. It has been
explained that electrical work is measured in watts
and that watts are found by multiplying the voltage
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ELECTRIC LIGHTING AND ENGINE STARTING 31
by the amperage. It will be realized that with a given
amount of work to be done, the wattage will remain
the same, and with the higher voltage the amperage
may be reduced in proportion. The size of wire re*
quired depends on the amperage to be carried and not
on the voltage, therefore a reduction in amperage
allows of economy in wire.
The wiring system of the car includes the units
that are necessary in making secure connections of
low resistance, the switches that give the driver con-
trol of the system, fuses and circuit breakers for pro-
tection against excessive flov, and the conduits and
other carriers for the conductors. While some parts
of the wiring may be used only for purposes of charg-
ing, of lighting or of starting, other wires may be
used for two or for all of these functions.
STARTXNG SYSTEM
The electric starting system makes use of an electric
motor that is connected to the battery through the
starting wires and the starting switch. The construc-
tion of the motor is similar to that of the dynamo
already described. It comprises an armature with its
commutator and brushes, all mounted on a shaft ; also
field magnets and field windings. The difference be-
tween a dynamo and motor does not lie in their con-
struction, but in the fact that power is converted into
electric current by the dynamo, while the motor con-
verts electric current into power.
When current is led to the motor, it magnetizes
the field magnets and also magnetizes the armature.
The reaction between the two magnetic fields causes
the armature to revolve within the field and power
to be produced.
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32 STARTING AND LIGHTING
The construction of the type of motor nsnally em-
ployed is somewhat simpler and more rugged than that
of the dynamo, the windings being much heavier and
a lesser length of wire being used in their construc-
tion. The connections and current carrying parts in
the motor must be of very low resistance, which
means well made. This is true because the amperage
to be carried is very large and the pressure or voltage
is comparatively low. A slight inc|:ease in the resist-
ance at any joint will offer such great opposition to
the low voltage that the flow will not be sufficient to
handle the work properly. When it is realized that
the amperage passing through an ordinary starting
motor, if supplied at the voltage used in ordinary
power circuits, would develop about forty-five actual
horsepower, the necessity for careful handling to
avoid loss will be appreciated.
The same rules apply to the starting switch and to
the wiring. They must have large current carrying
capacity and must be securely and carefully connected
so that the heavy currents may be handled without
great loss. Fortunately, these parts are simple and of
comparatively large size.
Because of the similarity of construction of djnia-
mos and motors the two units are often replaced with
a single machine having but one armature and one set
of field magnets. The armature may have one set of
windings and one commutator on its core or may have
two sets of windings and two separate commutators
and sets of brushes. The fields may likewise have one
set of windings or more than one set, some being used
for generating purposes only while the others may
come into use only when the machine is acting as a
starting motor. This combination is called a **motor-
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ELECTRIC LIGHTING AND ENGINE STARTING 33
dynamo" and, while having certain disadvantages
electrically, has the undoubted advantage of mechan-
ical simplicity and comparative ease of mounting to
offset its slightly lower efficiency in the use and gen-
eration of current.
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CHAPTER II
LIGHTING DYNAMOS AND STARTING MOTORS
The size and capacity of a dynamo for a certain
installation depends on the number of lamps to be
used and their candlepower, also on the amount of
power required to start the gasoline engine. The use-
ful work that may be accomplished with the current
supplied from the dynamo depends on the voltage
. and amperage, that is, on the number of watts. The
output of dynamos is measured in amperage and de-
pends to a certain extent on the speed at which the
armature is turning. The exact ratio of output to
speed depends on the type of regulation that has been
adopted for the dynamo. Some forms of regulation
allow the amperage to rise rapidly to its maximum
value and then to remain practically constant, without
increase or decrease, at all higher speeds. Other forms
of regulation provide for a gradual rise from zero to
maximum and allow the amperage to increase with
the speed over practically the whole range. Still
other regulating methods provide for a comparatively
quick rise to the maximum amperage and then cause
the amperage to decrease with greater dynamo speed.
In some cases the amperage delivered by the dynamo
is determined by the voltage of the battery, the am-
perage becoming less and less as the battery voltage
increases with the approach to a fully charged con-
dition. The practice is often followed of automatically
increasing the dynamo output when any or all of the
34
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LIGHTING DYNAMOS AND STARTING MOTORS 35*
lamps are turned on, this action serving l!o compen-
sate for the additional load imposed by the lamps.
It will be seen from the foregoing statements that
no general conclusions can be drawn and no general
rules given by which it may be determined whether
or not a dynamo is giving its proper amperage. If
the characteristics of the particular machine being
considered are known, the work is made easy ; but in
the absence of this information it is generally neces-
sary to make additional tests on other units, such as
the battery. These tests will show whether the dynamo
is doing its proper work provided everything else is
known to be in condition for efficient use. There is
but one rule that may be useful in the superficial
checking of the d3niamo operation; this rule being
that an ammeter attached to the battery should show
a slight charge with all lamps turned on and the en-
gine running between fifteen and eighteen miles per
hour car speed.
The rule as stated will almost always hold good, and
if the ammeter should show a discharge under those
conditions it is safe to assume that the dynamo is
not giving sufficient output or else that some trouble
exists between dynamo and battery that is preventing
the proper charge from entering the battery. It is
of course assumed that the lighting system and wiring
is in good order while making the test.
An error is often made in the application of this
•rule, it being stated that the dynamo output at a car
speed of fifteen miles per hour should be equal to the
discharge from the battery with all lamps turned on.
The two statements are not equivalent because of the
fact that so many important systems of regulation
increase the dynamo output with the lamps turned on,
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36 STARTING AND LIGHTING
but allow it to fall to a low value with the engine
nmning and the lamps turned off.
If it is desired to test the condition of the djniamo
only, the test should be made at the dynamo itself.
If it is desired to test the actual charging conditions
on the car, the test should be made at the battery,
because it is the charge that enters the battery that is
of importance. The dynamo might be doing all that
could be expected of it, but the current generated
would be of no use unless it was reaching the battery,
lamps, etc.
In testing the output of a d3niamo, an ammeter
should be inserted between one of the dynamo ter-
minals that carries charging current and a wire end
removed from this same terminal. A test made be-
tween the positive and negative terminals of the
dynamo would not give the same results under ordi-
nary conditions. With a majority of the dynamos in
use, a storage battery, or its equivalent in 'resistance,
must be in the dynamo circuit while making the test,
because the output of the dynamo depends on its
having to make an effort to force the current through
the battery. Additional information on making such
tests will be given, but the foregoing precautions
should always be observed and were mentioned thus
early because of the misunderstanding that so often
exists.
FIELDS AND FIELD VTINDINGS
A large percentage of all d3niamos in use at the
present time use electromagnetic fields, that is, field
magnets of soft iron which are magnetized by current
that flows through coils of wire placed around the
field magnet cores. Dynamos have been built that use
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LIGHTING DYNAMOS AND STARTING MOTORS 37
field magnets made of hardened steel, which when once
magnetized will retain their magnetic properties over
long periods of time in ordinary use. Others have
been built with these permanent magnets in combina-
tion with electromagnets. All forms of dynamos
using permanent magnets are comparatively rare and
their use is decreasing.
As previously mentioned, dynamo field magnets
may be built so that the armature rotates between a
single pair of magnet ends or poles, or else the con-
struction may allow for four, six, or more magnet
poles. A two-pole machine may have coils of wire
on each of the poles or it may be built with the coils
placed on only one pole. In the latter case the un-
wound pole is called a consequent pole and is of oppo-
site polarity from the wound pole; that is, if the
wound pole is positive, the unwound one will be
negative, and if the wound pole is negative, the un-
wound one will be positive. Pour-pole machines gen-
erally have but two of the poles wound, these two
being of the same polarity, both positive or both nega-
tive. On each side of the armature and half way
between the wound poles will be two consequent or
unwound poles of polarity opposite to the wound
poles.
Two-pole machines have two brushes to collect the
current from the armature, one positive brush and one
negative brush. Four-pole and six-pole machines may
have four or six brushes respectively, or may be con-
structed in such a way that but two brushes are
required, regardless of the number of poles.
As previously mentioned, the method of connecting
the field windings with the armature brushes is of
great importance in design, and in fact forms the
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38
STARTING AND LIGHTING
principal difference between dynamos of different
types. It will be realized from the explanation of
the poles already made, that the field windings may
be on one or more than one of the pole pieces, Figure
11. The number of windings, or the number of poles
that are wound, does not affect the principles used
in connecting the windings ; the variation in the num-
ber of parts or poles
simply means that the
winding are divided
into several parts or
are all on one pole
piece. This under-
standing will make it
unnecessary to refer
to the number of
poles in the following
explanation of the
various methods of
winding.
Figure 12 shows
the field windings
and their connections for a plain '* shunt wound" dy-
namo. The right-hand brush is positive and the cur-
rent generated in the armature passes from this brush
through the heavy wires to the outside circuits, return-
ing through the other outside wire to the left-hand
negative brush. It will be noted that one end of the
coil of wire around the field magnet is attached to the
positive brush while the other end of this field coil is
attached to the negative brush. This connection allows
a part of the current from the armature to pass
through the field magnet winding and thus mag-
netize the iron core. The direction of flow around the
Figure 11. — -Flow of Magnetism in
Field of a Four-Pole Siacbine.
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LIGHTING DYNAMOS AND STARTING MOTORS
39
magnet in this case causes the upper pole to become
positive and the lower one is therefore a consequent
negative pole without a winding. When two circuits,
such as the field circuit and the outside circuit, are
so connected to a source of current that a part of the
flow passes through each circuit, the circuits are said
Figure 13.— Series Field Winding.
to be in shunt with each other, and either one is called
a shunt with reference to the other. The field circuit
in Figure 12 is therefore a shunt of the outside circuit
and this dynamo is said to be shunt wound. This
form of winding, with several modifications, is by far
the commonest of all those in use for dynamos.
Figure 13 shows the connections that form a series
winding. This method of connection is not used for
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40 STARTING AND LIGHTING
dynamos unless in combination with a shunt, but is
shown because of its relation to this question. This
form places the armature and the field winding in the
same circuit and so that all of the current passing
into or out of the armature must also pass through
the field winding. Any circuit in which all of the
current that passes through any one part must also
pass through each and every other part is said to be a
series circuit, and inasmuch as the method illustrated
in Figure 13 conforms to this rule the dynamo would
in this case be series wound. As stated, this form is
never used for automobile lighting dynamos.
For d3niamo work, the series winding is useful when
combined with the shunt in either of two forms. One
combination is called ** compound wound,'* while the
other is called a ''reversed series" winding. In either
case the series winding is used to assist in dynamo
output regulation.
The direction in which the field current passes
through the wire composing the field winding deter-
mines the polarity of the magnet ends. When looking
at the end of an electromagnet, should the current be
fiowing around through the magnet winding in the
direction that the hands of a clock travel, then the
end being looked at is the negative pole ; while, if the
current travels in an anti-clockwise direction, the end
being observed is positive. The magnetic strength of
the field is determined by the number of turns of
wire around the pole and the amperage passing
through the wire. The number of turns of wire mul-
tiplied by the number of amperes flowing gives the
number of ''ampere-turns," and the strength of mag-
nets is determined by the ampere-turns. It will be
seen that the strength of the field in any dynamo de-
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LIGHTING DYNAMOS AND STARTING MOTORS
41
pends on the number of ampere-turns acting on the
metal of the field magnets, the strength becoming
greater with increase of ampere-turns. The output of
the dynamo depends on the strength of the field and
the speed of rotation of the armature, therefore, if
the speed remains constant the voltage and amperage
will depend directly on the field strength, or on the
number of ampere-turns acting to produce the mag-
netic field.
The connections used in making a compound wound
dynamo are shown in Figure 14. It will be seen that
V ^>-4^
Figure 14. — Compound Field Winding.
the shunt winding is exactly similar to that shown in
Figure 12, while the series field winding has been
added just as it is placed on the magnet of the dynamo
shown in Figure 13. It should also be noted that the
flow of current through both shunt and series field
coils is in the same direction, therefore they both tend
to produce the same polarity in the field magnets and
the series winding adds its effect to that of the shunt
coil and in the same direction. The greater the flow
through the series winding in the compound wound
machine, the greater will the output of the dynamo
become, while a decrease of flow through the series
coil will lower the output.
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42
STARTING AND LIGHTING
The reversed series connection is shown in Figure
15 and it will be seen that the whole diflference be-
tween this form and the compound wound machine
lies in the diflference in direction of the flow through
the series field. In this case the shunt winding is
acting at all times to make the upper pole positive
and of a strength corresponding to the ampere-turns
in the shunt coil. All of the current that leaves the
dynamo must pass around the series winding and
inasmuch as this current flows through the series coil
Figure 15. — Reversed Series Field Winding.
in a direction opposite to that of the shunt field cur-
rent, its eflfect will be to oppose the shunt field and
weaken the total strength of the magnet.
The normal tendency of the dynamo would be to
increase the voltage and output in amperes with in-
crease in speed, but this same increase of output pass-
ing through the reversed series winding tends to over-
come part of the strength of the shunt field, weaken
the magnet, and reduce the output. With this form
of winding it is impossible for the dynamo output to
exceed a certain value because of the opposition intro-
duced by the series winding and djniamo regulation is
thereby obtained.
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LIGHTING DYNAMOS AND STARTING MOTORS 43
On^ brush or one set of brushes will always be posi-
tive and the terminal connected to the positive brush
side is then called the positive terminal. The remain-
ing brush or set of brushes with the corresponding
terminal or connections will then be negative. Should
the flow of current around the fields be reversed in
direction, the polarity of the brushes will also be
reversed. With some designs of dynamo it is not
desirable that such a thing should take place, while
with others it is immaterial.
The initial flow around the flelds is determined by
the direction of the flow from the armature into the
brushes and the direction of this flow from the arma-
ture is determined by the direction of magnetic flow
between the field magnet poles, that is to say, the flow
is determined by which pole is positJ^e and which
negative. It is assumed in this case that the direction
of armature rotation remains the same at all times.
Because of the fact that the field magnets are mag-
netized by the flow of current around them it is often
asked how the dynamo starts to generate, inasmuch
as there can be no flow to start with and therefore no
magnetism produced. This difficulty is taken care of
by a natural characteristic of iron, this being the
practical impossibility of completely demagnetizing
the metal. A certain amount of magnetism, called
** residual magnetism," will remain in the softest iron
field cores even with the dynamo idle. When the
armature starts to rotate this residual magnetism,
which is the same in polarity as that obtaining when
the dynamo last operated, causes a slight flow of lines
of force through the armature. This allows a low volt-
age and small current to be generated in the arma-
ture, and this small current flowing through the field
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44 STARTING AND LIGHTING
coils strengthens them to such an extent that the
current flow is further increased. The dynamo
''builds up" very rapidly in this way until the full
voltage and output is reached.
If the flow of current around the fields should be
reversed from its usual direction, the residual mag-
netism remaining would be of opposite polarity from
the normal, and when the dynamo was again used its
terminal polarity would be changed. That is, the ter-
minal that was positive would be negative and the
terminal that was negative would be positive. Should
this condition remain, the dynamo would send its cur-
rent through the battery in the wrong direction with
the result that the battery would suffer an extremely
rapid discharge and would soon be damaged perma-
nently. '<
In order to restore the field magnets to the proper
polarity it is necessary that a flow of current be sent
through the windings in the proper direction. Should
a test at the djtnamo show that the current flow re-
mains in the wrong direction, it may be corrected as
follows: First make sure that the connections be-
tween dynamo and battery are correctly placed. This
means that the positive side of the battery should be
connected to the dynamo terminal that should be
positive, while the negative side of the battery should
be connected to the dynamo terminal' that should be
negative. With these connections made, with a fully
charged battery, and with the dynamo idle, the cut-
out should be closed several times and allowed to
remain closed for two or three seconds each time.
Should the cut-out tend to remain closed (if of the
electromagnetic type), starting the engine will allow
it to open. The flow of current through the dynamo
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LIGHTING DYNAMOS AND STARTING MOTORS 45
under these conditions will restore the proper po-
larity at its terminals. Many types of dynamos now
in use change their polarity to that of the battery the
first time that the cut-out closes, and in this case it
would not matter which way the connections were
placed as far as the dynamo and battery were con-
cerned.
The above remarks regarding dynamo polarity do
not apply to machines having permanent magnet
fields. With permanent magnets placed on the dy-
namo in a certain position, the brushes and terminals
will be of a polarity that corresponds to the position
of the positive and negative magnet poles with refer-
ence to the armature. Removing the magnets and
replacing them in a position exactly opposite to the
one originally occupied while the direction of rotation
remains the same will reverse the polarity of the
dynamo brushes and terminals. This polarity can
only be restored to normal by replacing the magnets
in their proper position. No amount of flow from the
battery through the dynamo will have any eflfect on
the fields for the simple reason that this flow of cur-
rent does not pass around or affect the flelds in the
same way as with the electromagnetic type previously
. discussed. A flow of battery current through the dy-
namo in a wrong direction, however, will serve to
weaken the permanent magnets of this type of machine
and every precaution should therefore be used to avoid
wrong connections in the wiring.
The polarity of any wire or any terminal may al-
ways be determined by attaching extra lengths of wire
to each of the terminals or each side of the circuit to
be tested. If the loose ends of these wires be then
immersed in water to which has been added a small
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46
STARTING AND LIGHTING
quantity of acid or salt, the wire attached to the nega-
tive side will give the greater amount of bubbles,
Figure 16. The wire attached to the positive side
will show very few, if any, bubbles. In making this
Figure 16. — Water Test for Polarity of Wire Ends.
test the wire ends should be separated by one-fourth
to one-half inch. This test may be applied to dynamos
while they are in operation, to batteries, or to any
other wires when both sides of the circuit may be
reached.
ARMATURE
With very few exceptions, all lighting dynamos are
made with a form of armature known as the **drum
Figure 17. — ^Arrangement of Coils on a Drum Armature.
armature." The coil and commutator connections for
this type are shown in Figure 17. This illustrates
the principle used in handling the work by showing
the connections for four coils and four commutator
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LIGHTING DYNAMOS AND STARTING MOTORS 47
bars. In actual practice this number is increased
according to the size of the machine. It will be seen
that the ends of one coil attach to adjacent commu-
tator bars in such a way that all of the coils and. all
of the bars are electrically connected with each other.
The bars are insulated from each other and the coils
are insulated in each case, the interconnection being
secured between coil and bar in each case, and not
from coil to coil or from bar to bar. The design of
such armatures is not important to the present discus-
Figure 18. — ^Arrangemeat of Coils on a Ring Armature.
sion, but the connections should be understood be-
cause they make clear the results that are secured in
certain tests.
Another form of armature sometimes found in this
work is that known as the *' Gramme'' type, or the
**ring armature." The construction and connections
for such an armature are shown in Figure 18. The
armature core is in this case a hollow ring in place
of a solid cylinder, but the connections between the
coils and commutator bars and the complete circuit
around the whole armature remain practically the
same in effect.
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48
STARTING AND LIGHTING
COMMUTATOR
This part of the dynamo, in connection with the
brushes, changes the alternating current generated in
the armature windings to a direct current suitable for
battery charging. The commutator consists of a series
of copper bars arranged in a ring around the arma-
ture shaft and separated from each other by strips
of mica or other insulating material. The commu-
tator segments are connected to the armature windings
B^gure 19. — Commutator Construction.
as shown in Figures 17 and 18 and the brushes are
carried in holders in such a position that they bear
on the surface of the commutator in the best posi-
tions for the collection of the current at proper volt-
age and amperage.
A longitudinal section through the commutator end
of a djniamo armature is shown in Figure 19, this
illustration indicating the proportions generally used
for the commutator bars. It is necessary that the
copper used be of a high degree of conductivity so
that it will carry the current without undue heating
and it is also necessary that the bars be of a depth
sufficient to allow of a certain amount of wear from
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LIGHTING DYNAMOS AND STARTING MOTORS 49
the brushes before the surface of the commutator
comes down too close to the insulation on which the
bars are supported from the shaft.
It is very essential that the insulation between ad-
jacent segments be perfect, otherwise the coil to which
these segments attach will be short circuited and the
operation of the dynamo will be effected.
In order that the brushes may make a good contact
with the surface of the commutator, this surface must
be maintained in proper condition. That means that
the commutator surface must be smooth and perfectly
cylindrical in the form generally employed. Should
the surface become dirty, scratched, rough or pitted
it must be restored to good condition at once if the
dynamo is to be maintained in good condition.
The commutator surface should be of a rather dark
brown color and should have a slightly gla«ed appear-
ance when in the best condition. Should an examina-
tion show it to be blackened or dirty it may be cleaned
by holding a soft cloth slightly moistened with gaso-
line against the commutator surface while the dynamo
is being driven by the engine at the slowest possible
speed. Oil should never be used on the surface of a
commutator, but lubrication may be provided by plac-
ing a small quantity of vaseline on a piece of soft
cloth or leather and holding it against the commutator
surface with the dynamo revolving. Even this lubri-
cation should not be used unless the commutator sur-
face shows signs of scratching after being cleaned.
In many makes of dynamos the brushes are made from
a composition that provides sufficient lubrication for
the commutator surface.
If the surface of the commutator is rough or slightly
scratched and pitted it may be dressed smooth with
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60 STARTING AND LIGHTING
sandpaper. Emery cloth or emery paper should never
be used because emery is an electrical conductor and
will short circuit the commutator bars. Before using
the sandpaper the commutator should be cleaned as
described, the brusHes should then be removed from
their holders or the holders and brushes should be
so supported that they do not touch the commutator
surface. The engine should be run at the lowest
possible speed so that the commutator is revolved. A
strip of **000'' sandpaper should then be cut just as
•wide as the commutator surface, no narrower under
any circumstances, and this strip of paper should be
placed over the end of a thin stick of equal width.
By holding this paper against the surface of the
revolving commutator slight scratches or pitting may
be removed. Care should be used to bear evenly on
the wjiole width of the commutator so that grooves
may be avoided.
After the surface is even and bright, the engine
should be stopped and every trace of cc^per dust and
sand should be removed from the interior of the
dynamo, either by wiping out with a cloth moistened
with kerosene or by blowing out with air oinder pres-
sure. The surface of the commutator will be im-
proved and made very smooth if a soft pine stick is
held against the surface while the engine is running.
The job should be completed by dressing the ends of
the brushes- as described in a following paragraphs
Should the commutator surface show deep grooves
or severe pitting it will be necessary to remove the
armature from the dynamo, place it in a lathe and
take the thini;iest possible cut from the surface of
the commutator. The comparatively slight thickness
of the commutator bars should be borne in mind and
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LIGHTING DYNAMOS AND STARTING MOTORS 51
no more metal should be removed than is absolutely
necessary to obtain a smooth surface.
After turning a commutator in the lathe it will be
necessary to ** undercut'' the insulation between the
segments. It will also be necessary to perform this
operation should the insulation be found even with
or slightly above the surface of the copper bars at
each side. To undercut the insulation means to re-
move sufScicnt material from the exposed edge so
that its surface is about 1/32 inch below the surface
of the copper bars.
The removal of the insulating material may be ef-
fected by using a very thin hack saw blade and exer-
Figure 20. — Undercutting Insulation Between Commutator Segments.
cising great care to avoid bridging from segment to
segment with fine particles of copper. Figure 20
shows a partial section through a series of commuta-
tor bars, the white spaces representing the copper
segments and the black portions the insulating mate-
rial. At A and B are shown pieces of insulation that
require undercutting. At C and D are shown sections
when the work has been properly done and at E and F
when improperly done. When the insulation is re-
moved it must be taken out so that the surface is flat
and the comers made with the copper segments are
square. A knife file should be used following the hack-
saw blade so that the comers may be cleaned out. If
the surface of the insulation is left grooved the work
will be practically valueless.
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62 STARTING AND LIGHTING
Sparking at the brushes is usually caused by a com-
mutator surface in poor condition, by improperly
fitted brush ends, or by high insulation between the
segments. Sparking may also be caused by brushes
that do not rest on the commutator in the proper
position, although this condition should not be met
with unless the dynamo has been taken apart and
wrongly reassembled. Other causes of sparking may
be in the brushes themselves or trouble in the arma-
ture windings, which will be taken up in a later
chapter.
While an examination of the commutator is being
made it will be advisable to look carefully for seg-
ments that are loose, or too high or too low, that is,
higher or lower than those adjoining. Loose segments
will necessitate the return of the dynamo or armature
to its makers, although high or low segments, pro-
vided this condition is not caused by looseness, may be
corrected by turning the commutator in a lathe.
It will be noted that the wires coming from the
armatUx e windings are fastened to the commutator
bars by soldering. These wire ends should be exam-
ined to make sure that they are tight, because the
excessive heat that is sometimes generated in the dy-
namo may melt the solder and cause it to be throwii
out of place. The remedy is to replace the wire ends
and resolder them with hard solder and neutral flux.
BRUSHES
The brushes that collect current from the commu-
tator are generally made from very fine grained car-
bon and this carbon is often combined with other
substances such as graphite for purposes of lubrica-
tion and smooth running. Metal brushes made from
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LIGHTING DYNAMOS AND STARTING MOTORS 53
tightly wound coils of copper wire gauze are some-
times used, although they are comparatively rare.
Brushes are sometimes macie by placing carbon around
a copper core, the use of any one type depending on
the design of the dynamo and the ideas of the makers.
Because of the fact that it is not always possible to
know just what calculations and allowances have been
made in the design of the machine, it is a safe rule to
follow always to replace brushes with others secured
from the makers of the machine being handled. While
other brushes might be satisfactory, there is always a
doubt.
Figure 21. — Pitting Brush-End with Sandpaper or Cloth.
The electrical resistance between brush and com-
mutator depends chiefly on how well the brush end fits
the commutator surface against which it bears. High
resistance lowers the efficiency of the dynamo and is
the primary cause of more serious troubles. For these-
reasons the brush ends should always be properly
fitted. This operation is performed as follows:
A strip of **000" sandpaper should be cut so that it
is at least as wide as, and preferably a little wider
than, the end of the brush to be hfifndled. With the
dynamo idle, the brush should be drawn away from
the surface of the commutator so that the strip of
paper may be drawn between the brush end and the
commutator with the sand side toward the brush.
Figure 21. The paper should then be drawn back and
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54 STARTING AND LIGHTING
forth under the brush end and should be held so that
it follows the surface and curve of the commutator
while passing under the brush. The sand will remove
enough of the brush end to allow a perfect fit on the
commutator surface to be secured. After all rough-
ness and unevenness have been removed from the
brush, the end should be carefully wiped with a clean
soft cloth. All particles of dust should be removed
from the interior of the dynamo with a cloth moistened
with kerosene or by blowing them out with air. Each
brush should be dressed in this way, even though only
one seemed to need the treatment. Great care should
be used in dressing the ends of regulating brushes
(the use of which will be explained in Chapter V),
and they should always be dressed after moving them
to a new position. It is absolutely essential that the
brush ends shall make perfect and full contact over
their entire section.
The brushes are practically the only part of the
dynamo that will require periodical replacement. It
is not possible to state any definite time that brushes
should last ; this depends on the design and construc-
tion of the dynamo. They should be examined occa-
sionally and their length noted. When it is seen that
they can wear only one-eighth of an inch more before
allowing their holders or springs to touch the commu-
tator, they should be removed and replaced with new
ones. A brush should be expected to wear at least a
year, although this time may be affected by many con-
ditions. New brushes should always be fitted to the
commutator surface by the method described above.
The brushes are carried in the proper position by
holders of various forms. Some holders fasten tightly
to the brush and m^ve with the brush as it wears and
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LIGHTING DYNAMOS AND STARTING MOTORS
66
as it follows the commutator surface, Figure 22.
Other forms of holder provide that the brush slide
freely in the holder, and in this case the holder itself
remains stationary. In all cases the brushes are insu-
lated from the holders or else the holders are insulated
from the balance of the dynamo parts. Attached to
the brush is a short length of flexible wire, usually
called the brush ''pigtail," and it is through this wire
that the current is taken from the brush to the ter-
minal connections, or in some cases, to a connection
with the metal of the dynamo case for ground return
systems.
Figure 22. — Pivoted and Sliding Brush Holders.
The brush should be free to move at all times. If
fastened securely to the holder, the holder should be
free to move on the pivot that supports it, and if any
binding is present, the dynamo output will be af-
fected. If the brush slides in the holder, care must
be used to see that the sides of the brush do not bind
under any conditions. Should binding be found at
this point, the sides of the brush may be carefully
dressed with a fine file until a free sliding fit is
secured.
The brushes are held against the commutator sur-
face by means of springia of various forms and types.
The tension of these springs is usually adjustable by
some means, either by moving one end of the spring
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56
STARTING AND LIGHTING
from notch to notch of an adjustment segment, by-
tightening or loosening a holding screw or by some
other easily discovered means. The tension on
brushes varies from an ounce or two up to nearly two
pounds, depending on the design and requirements.
In all cases the tension should be sufficient to main-
tain a good running contact, that is, so that the dy-
namo output will not be impaired and so that spark-
Figure 23. — Testing the Tension on Brushes by Means of Spring
Balance.
ing will not take place with other factors taken care
of. The tension should be as low as is possible and
still secure good contact. More than this will cause
excessive wear and overheating. See Figure 23.
STARTING MOTORS
The starting motor embodies the same principal
parts as the dynamo, that is, it consists of an arma-
ture with its commutator, a set of brushes, field wind-
ings and field magnets. The most apparent differ-
ence between these units is in mechanical construction,
the motor being heavier and being made from larger,
stronger parts. Outside of the difference in action.
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LIGHTING DYNAMOS AND STARTING MOTORS 67
the most noticeable electrical change is in the method
of connecting the field windings. For motors that are
separate units, that is to say, motors that are not
combined with the dynamo, the series field winding is
invariably used because its characteristics are more
desirable for the work of starting. ^
It will be seen from an examination of Figure 13
that a series winding would send all of the current
passing through the machine into the fields and then
this total flow of current passes through the armature.
The magnetic strength of the fields becomes greater
with increase of current fiow and by thus sending the
whole fiow through the fields they are made of the
greatest possible strength. The same statement ap-
plies to the armature, the great volume of current
making the armature pull as great as can be secured.
The maximum fiow of current through a starting
motor varies according to the difficulty pf starting the
engine from rest, being large in some cases and com-
paratively small in others. At a pressure of six volts
the starting amperage may be anywhere between
seventy-five and three or four hundred. With higher
voltages the amperage is reduced for the reason that
the power is measured in watts and the same number
of watts may be secured by using a higher voltage
with a smaller fiow.
The power required in starting is usually between
one-half horsepower and two horsepower, depending
on the size of the engine and its design. This starting
load puts a very severe strain on the battery, and if
the fiow is allowed to continue for more than a few
seconds, great damage may result. The form of bat-
tery used for this work is well able to stand these
heavy discharges and it is not the amperage of dis-
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68 STARTING AND LIGHTING
charge that does harm so much as the withdrawal of
such a great percentage of the available current from
the battery. Fifteen minutes of rapid running will
just about make up for the current drawn during
thirty seconds' use of the starter with an engine thfet
is rather hard to crank, and for this reason the starter
should be carefully used and never demonstrated or
used unnecessarily. The final result of improper use
of the starter is a discharged battery, and it is this
condition of discbarge that harms the battery, not the
heavy current drawn for starting.
In order to allow a motor of reasonable size to do
the work it is connected to the engine through reduc-
tion gearing of some form. This gearing may take
the form of chains or may be made up of spur, bevel
or worm gears in combination with suitable shafting.
The drive ratios ordinarily employed allow the start-
ing motor to nln from five to twenty-five times as
fast as the engine crankshaft is revolved during the
cranking operation. This ratio applies to starting
motors that are separate units. Combined motor-
dynamos usually have lower ratios, and in fact in some
cases may operate at engine speed. A very common
ratio for motor-dynamos is between two and one-half
to one and three to one.
MOTOR-DYNAMOS
This word is used to designate the machines that
are combined electrically, having one or more parts
that perform functions during the generation of cur-
rent as well as during the starting operation. The
machine in which a separate motor and dynamo are
enclosed by the same housing is not called a motor-
dynamo in this book.
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LIGHTING DYNAMOS AND STARTING MOTORS
59
In all motor-dynamos it is necessary to provide two
field windings, one a series winding for starting motor
action and the other a shunt winding for the efficient
generation of current, Figure 24. In some cases an
additional winding is used for the purpose of regu-
lating the output of the machine as a dynamo. In
this last case the field magnets will carry a shunt
winding for generating, a reversed series winding for
output control and another series winding of heavier
conductor for starting the engine as a motor. This
system is used in Splitdorf motor-dynamos.
Figure 24. — Compound Wound Motor-Dynamo (Ryneto Type).
Other designs make use of a third field winding for
purposes of regulation, but do not use the reversed
series connection. One of these is found in the U. S. L.
system which incorporates a compensating coil on one
of the field magnet poles, this coil being energized
through the current drawn off the commutator by a
regulating brush. The action of this compensating
coil is to assist the shunt windings at low speeds, but
to oppose them at high speeds because of the change
of direction in the current flow through the regulating
brushes.
Motor-dynamos make up a very important class and
also a very large proportion of the applications in use.
They may be divided into several types, according to
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STARTING AND LIGHTING
their construction and the principlQS involved in their
operation. While the two types just mentioned par-
take somewhat of the characteristics of those to be
mentioned hereafter, they should be considered sep-
arately because of the" additional field winding that is
used to produce the regulation of current.
One of the commonest classes of motor-dynamos is
the one making use of a machine with one armature
with one commutator for both starting and charging.
The fields carry a shunt and a series winding. Dur-
Figure 25. — Compound Wound Motor-Dynamo Providing Reversed
Series Regulation.
ing the starting operation the current floW passes
through these windings in such a direction that they
assist each other and the machine becomes a compound
wound starting motor. When the speed of the motor-
dynamo is increased to a point at which its generated
voltage will overcome the battery voltage, it becomes
a dynamo with the shunt field current flowing in the
same direction as during starting, but with the series
field current flowing in the opposite direction. This
makes it a dynamo with a reversed series field coil,
and this reversed series winding serves to limit the
amperage during charging. This action is shown in
Figure 25. When the starting switch 8 is closed, the
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LIGHTING DYNAMOS AND STARTING MOTORS 61
battery current flows through the positive wire 1 and
around the series field winding in the direction of the
arrows, thence through the wire 2 to the right-hand
brush, through the armature to the 'left-hand brush
and to the battery through the negative wire 3, The
right-hand brush is positive and the left-hand one
negative. Current then flows from the positive brush
side through the wire 4 and around the shunt field
coils in the direction of the arrows and back to the
negative brush side. It will be seen from the arrows
that the current flow is in the same direction around
both field windings.
Now consider what happens when the dynamo volt-
age overcomes that of the battery. The flow of cur-
rent will then be from dynamo to battery and at the
instant of reversal there will be no flow through the
series field, although the flow will continue through
the shunt coils. This is true because the current stops
coming from the battery and for a moment might be
said to stand still in the lines connected to the battery.
The dynamo voltage is now causing a flow through the
shunt field in the original direction and because the
fields are maintained with the same polarity the right-
hand brush remains positive. With the flow from
dynamo to battery, the direction of current through
the shunt coils will be as shown by the arrows, but
the flow through the series fleld will have been re-
versed and will be in the direction opposite to the
arrows, which of course causes the upper coils to be-
come a reversed series winding. A reverse current
cut-out may or may not be used with this system.
Some makers, such as AUis-Chalmers, use an electro-
magnetic cut-out, while others, like Dyneto and Entz,
allow the dynamo and battery to remain connected as
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62
STARTING AND LIGHTING
long as the starting switch is closed. This subject
will be more tully covered in Chapter V.
Another class of motor-dynamos makes use of a
series and a shunt field winding, but with the differ-
ence that the series field is not used as the principal
method of current control, while the shunt field is
neglected, or is of minor importance, during charging.
These machines make use of an automatic cut-out in
the charging circuit which opens the connection be-
tween battery and dynamo when the dynamo voltage
u
I
I
^
rt_< Out.
5tart
—^
. >
\
J " "
V^J
Figure 26. — ^Motor-Dynamo with Separate Regulator and Cut-Out.
is below that of the batteiy and while the starting
switch is open. The connections for such a system
are shown in Figure 26, which illustrates the prin-
ciple involved, although in practice the wiring is not
always placed exactly as shown for manufacturing
reasons. With the starting switch 8 closed, current
fiows from the battery through the wire 1 and the series
field to the left-hand brush, then through the armature
to the right-hand brush and back to the battery through
the wire 2. When the engine has been started and the
starting switch opens, the battery is disconnected from
the motor-dynamo by the open starting switch and by
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LIGHTING DYNAMOS AND STARTING MOTORS 63
the cut-out which is always open when the dynamo
voltage is below that of the battery. When the
dynamo is running at a speed suflScient for charging,
the cut-out closes and the dynamo and battery are con-
nected through the wires 1 and 3 on the positive side,
and the wire ^ on the negative so that charging com-
mences. It will be noticed that the shunt field wire
leads to the regulator and the dynamo output is con-
trolled by the action of this regulator in limiting the
shunt field current. The current from the left-hand
brush passes to the shunt field, then through the wire 4
to the regulator and back through the wire 5 to the
right-hand brush. The current that flows through the
series field to the cut-out during charging passes in a
direction the reverse of that found during starting so
that this series field acts to limit the dynamo amper-
age. This action is not depended on altogether, but
the additional regulator in the shunt field circuit is
supposed to perform this function. This is the prin-
ciple used with Allis-Chalmers motor-dynamos, also
with North-East, Remy, and Simms-Huff units. .
Other motor-dynamos use an automatic cut-out, but
control the dynamo output by other means than the
one shown in Figure 25. For example, Wagner,
Bi jur, and Westinghouse motor-dynamos use the
''third brush'* method of control, while Jesco motor-
dynamos make use of a ''bucking coil'* on the field
magnets, both of which methods of control will be
explained in Chapter V.
Still another class of motor-dynamos, represented
by Delco equipment, makes use of a shunt and a
series field winding and also provides separate wind-
ings and two separate' commutators for the armature.
The principle of connection used with such a machine
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64
STARTING AND LIGHTING
is shown in Figure 27. With the engine idle the
open cut-out switch disconnects the battery from the
brushes on the dynamo commutator D and also from
the lower shunt field. The dynamo or current gen-
erating part of the unit is therefore inoperative. When
the starting switch 8 is closed, current flows from the
battery through the wires 1 and 2 to the upper series
field and then through the wire 3 to the brush resting
Figure 27. — Double Commutator Motor-Dynamo with Manual Cut-
Out (Delco Type).
on the motor commutator M. Passing through the
motor windings on the armature, the current returns
to the battery through the wire 4 and the engine is
started.
With the engine started, the switch S is allowed to
open and the series field and motor windings on the
armature are no longer energized. The motor-dynamo
is then driven by the engine as a dynamo and with
the cut-out switch closed, current flows from the
dynamo commutator D through the brushes and wires
5, 6 and 7 to the battery for charging. The shunt
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LIGHTING DYNAMOS AND STARTING MOTORS
65
field is connected to the dynamo commutator brushes
and the flow through the field windings is controlled
by the regulator. The shunt field current passes
from the upper brush through the field windings, then
through wire 8 to the regulator and back through wire
9 to the lower dynamo brush.
COMBINED UNITS
While the separate dynamo and motor, together
with the motor-dynamo, make up by fat^ the greater
part of all the equipments in use, other combinations
Figure 28. — Ignition-Dynamo (Remy).
* are found in lesser numbers. One of these is the ig-
nition-dynamo. This machine is made by attaching
to a separate dynamo of any type the devices that
are necessary' for the production and distribution of
the ignition current for the spark plugs.
One type of ignition-dynamo. Figure 28, makes use
of a breaker, or interrupter, and a high tension dis-
tributor of the conventional magneto type mounted on
one end of the dynamo, either the end that carries the
dynamo commutator and brushes or the opposite end.
The operation of these ignition parts differs in no way
from the operation of similar ones used on magnetos,
the attachment to the dynamo being made sirapily be-
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STARTING AND LIGHTING
cause it affords an economical method of mounting
and does away with the . necessity for providing a
separate magneto with its drive and base. The com-
bination of these ignition parts in no wise affects the
starting and lighting features of the machine and in
this connection the ignition units may be disregarded.
It should be understood that this construction does
not allow for what is known as a ** self-contained high-
Figure 29. — Dynamo with Vertical. Ignition Head (Westinghousc).
tension '' magneto being incorporated with the dy-
namo, but uses a separate transformer coil just as does
the magneto of the type that requires a separately
mounted coil. This type of machine has been pro-
duced by Gray & Davis, National, Remy, and West-
inghousc.
Another consolidation of electrical devices is met
with when the ignition units are mounted on the
dynamo case and are driven from the same shaft that
drives the dynamo, Figure 29. In this case the igni-
tion parts include a breaker or interrupter together
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LIGHTING DYNAMOS AND STARTING MOTORS 67
with a high tension distributor carried in a small
housing and with their drive shaft attaching through
gearing in the dynamo drive shaft. The separate
transformer coil may be mounted on the dynamo or
may be carried at some other point on the car. This
combination is also called an ignition dynamo or
** dynamo with ignition.''
It is also possible to mount the type of ignition units
just described on a motor-dynamo just as they are
mounted on a dynamo. This is the construction so
often found with Delco installations, Figure 30, and
harfalso been used by such makers as Remy. A single
piece of machinery then performs functions of start-
ing, lighting and ignition, and is often called a single-
unit machine. The term ''single unit" is commonly
applied to the motor-dynamo also, although its use in
this connection is somewhat confusing. The various
combinations may be distinguished by calling a sys-
tem made up of separate dynamo, separate motor
and separate ignition unit, a ''three-unit" system;
a motor-dynamo or ignition-dynamo with separate
ignition or motor, a "two-unit" system; and a motor-
dynamo with ignition a "single-unit" system.
The combination of motor and dynamo in one case
while making them separate electrical units is in
fairly common use. The electrical design of the parts
of the installation dobs not differ in any way from
that used when they are placed entirely away from
each other. When this construction is uiSed, the
dynamo unit is generally driven from the shaft or
chain sprocket that comes direct from the engine
crankshaft, so that a proper drive ratio for the dy-
namo may easily be secured. The motor is then
mounted at one side, or above or below the dynamo,
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68
STARTING AND LIGHTING
Figure 30. — ^Delco Motor-Dynamo with Ignitioii Head.
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LIGHTING DYNAMOS AND STARTING MOTORS 69
and drives to the main dynamo shaft through a re-
duction gearing that allows of the proper ratio for
starting without interfering with the dynamo drive.
See Figure 31. The dynamo is always driven while
the engine is running because of its direct connection
with the main drive shaft. The motor, however, is
only in operation while the engine is being started and
at all other times is allowed to remain idle and dis-
Flgure 31. — ^Double Deck Motor and Dynamo (Gray & Davis).
connected from the drive shaft. The location of the
units and the construction used with them will always
be apparent from an examination.
Some modifications of the types described are in
use, such as the tandem system, which places the
motor and dynamo end to end. They are mechanical
variations only and are not important from the elec-
trical ^ standpoint. Many such combinations are
adoptjBd because of the limited room or diflScult drive
connections that must be considered.
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CHAPTER III
STORAGE BATTERIES
Each cell of a storage battery contains two kinds
of plates, called positive and negative, made from
compounds of lead and immersed in a liquid composed
of sulphuric acid and water. A chemical action takes
place between the plates and the liquid and the result
of this chemical action is a flow of electricity through
wires that are attached to the battery terminals.
Therefore, the battery does not store, and does not
contain, electricity, but is capable of generating a
flow of electric current because of the action that
takes place in the battery. In order to bring the ele-
ments of the battery into such condition that they
will cause a flow of current, it is first necessary to
send a flow of electricity through the battery. The
energy of this current being sent through the battery
is consumed in making one series of chemical changes,
and when wires are connected to the battery, this same
series of changes takes place in a reverse order and
most of the energy absorbed from the flow of chain-
ing current is given back into the wires.
As already mentioned, the cells are made up of
plates and liquid. The plates are in turn made up
of a metal framework, called the *'grid,'' Figure 32,
and a paste, called the active material, with which the
spaces in the grid are filled. Adjacent plates are
prevented from touching each other by the use of
wood separators. Figure 33, placed between thenu
70
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STORAGE BATTERIES
71
The jar in which the plates, separators and liquid
are carried is made from some form of instdating
material, often containing rubber, compounds of
pitch and other materials that insulate while resisting
the action of the acid- in the liquid.
The grids are made from lead with which has been
alloyed antimony to give the metal the necessary stiff-
ness. Various designs and forms are in use, but they
consist in a general way of vertical and horizontal
Jl
li ifi ifT i n III i ll iii iin
D in ir III ifi u i n lo i
B in in III III in in in i
irnfi 111 111 Ml in in i n i
lL_lll_IL
DDZHC
3L-JII III IIIZ3
d]QZI] DZHIlZI] mZ] 11 III I II ~l
^ii_llLJlE
HE
II III in i n 111 III III in i
B in in 111 111 ifl III IB I
Figure 32. — Grid for Battery Plate.
bars usually spaced about three-fourths of an inch,
apart, measuring across the plate and about one-
fourth inch apart measuring up and down. The grids,
and consequently the plates, vary in thickness from
about one-eighth, inch up to three-eighths. The thick-
ness of the plate has a great deal to do with, the rat€ ia
amperes at which, current may be drawn from the bat-
tery. Very thin plates allow the liquid in the cell to
reach through them with comparative ease and a very
heavy current may be taken from such, a battery,
while the thicker plates will only allow comparatively
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72
STARTING AND LIGHTING
low amperages to be drawn through the wires. The
bars of the grid are formed and spaced in such a way
that they tend to hold the active material firmly in
place.
After the grids have been formed they are filled
with the active material by the process called ** past-
ing,'* and this form of plate is called a ** pasted
plate/' The active material is made from lead oxides,
sometimes combined with other materials to give hard-
Figures 33 and 34. — Positive Plates, Separator and Negative Plates.
ness and toughness and to make the plates porous so
that the liquid can act on the material. The mixture
is made into a paste with weak solutions of sulphuric
acid and water, and the spaces between the bars of
the grid are filled with this paste. After the material
has set or hardened, the pasted plates are assembled
with their separators in a jar. The cell contains an
uneven number of plates. Figure 34, there being one
more negative than positive, and the plates are placed
alternately and so that both outside plates are nega-
tive. The liquid, composed of acid and. water, is then
poured, into the jar until it covers the plates to a
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STORAGIB BATTERIES 73
depth of one-quarter to three-eighths of an inch above
their upper edges.
When the cell has been assembled all the positives
are joined together and all of the negatives are simi-
larly fastened together with connecting straps that
join the lugs cast at one of the upper comers of each
grid. The positive connecting strap is attached to
the positive terminal of the cell or battery, while the
negative strap is fastened to the negative terminal.
A flow of electric current is then sent through the
cells, the i)ositive side of the charging current being
attached to the terminal that will be positive and the
negative side of the source of current being con-
nected with the negative terminal. As this current
flows through the cells a change takes place in the
material of the plates and the positives turn to per-
oxide of lead while the negatives turn to sponge lead.
When the material in the grids has been completely
transformed, which usually takes several reversals of
current flow, the plates are said to be * 'formed" and
the battery is charged.
The positive plates are now dark red or brownish
red in color and are hard enough to resist scratching
with the finger nail. The negatives are gray and are
soft enough to be easily dented with any hard sub-
stance. The material must be porous in each case, and
water poured on dry positive plates should show
through on the opposite side almost immediately. It
is very desirable that the material in the plates be as
tough as possible, so that it will not readily fall to
pieces, and it should also be as lightweight as pos-
sible so that the surface exposed will be large when
compared to the total weight High grade batteries
of these types will deliver a power of between nine and
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74 STARTING AND LIGHTING
twelve watt-hours for each pound of weight, this
being the equivalent of from one and one-half tx> two
amperes flow at six volts pressure. The battery will
gradually deteriorate while in use, and when its age
is between eighteen months and three years, the nega-
tive plates wiU have suffered a change in the form
of the material so that it is an economy to replace the
battery with a new one,
'y tjK CELL
Inasmuch as all batteries must be made up of indi-
vidual cells and as all the cells in one battery are
exactly alike, the subject will be treated as the cell
rather than the battery, and it will be understood
that everything said about the cells applies to the
battery as a whole.
The voltage obtained from one cell does not depend
on the size or weight of the cell, as it is the same
whether the battery will give a flow of only a few
amperes or of several hundred amperes. The normal
voltage under operating conditions is two for the cell,
this voltage varying, however, with the state of charge
of the battery. When the material in the plates has
been completely changed to peroxide of lead and lead
sponge and the cell is fully charged, the cell voltage
may be as high as 2.5, while with the battery dis-
charged to a point at which no more current should
be drawn, this voltage will fall to between 1.7 and 1.8
for the cell. The voltage while being charged will be
higher than while being discharged, the charge voltage
being between 2.1 and 2.6, while on discharge the
voltage will usually run between 1.9 and 2.1. It will
thus be seen that the voltage of the cell may give some
indication of the condition of charge or discharge, a
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STORAGE BATTERIES
75
voltage below 2 indicating that the cell is discharged,
while a voltage of 2 or more indicates a satisfactory
condition of charge. It should be understood, how-
ever, that the voltage does not form an entirely de-
pendable indication because it is easily possible to
have a high voltage with a cell that is capable of giv-
ing very little flow of current for useful work, while
the voltage of a cell that is in good condition to do a
great deal of work may be rather low. In making
ordinary calculations it is customary to consider each
cell as causing a pressure of two volts. Therefore, a
Figure 35. — Six- and Twelve- Volt Batteries with Cells in Series.
three-cell battery is called a six- volt battery, a six-cell
battery is a twelve-volt battery, etc. It should be
borne in mind that a six-volt battery may give a
pressure of seven and one-half volts, a twelve-volt
battery may give fifteen volts, and so on for any
• voltage or number of cells.
In order that the voltage of the whole battery may
be equal to the number of cells multiplied by two, the
individual cells are connected in series with each
other. The series method, Figure 35, connects the
positive of one cell to the negative of the next and the
positive of the second to the negative of the third, and
this connection is carried throughout the battery if it
is desired to secure a voltage equal to the combined
voltages of all the ceUs. It is possible to make other
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76
STARTING AND LIGHTING
connections that will give a lower total voltage by-
placing a sufficient number of cells in series to give
the desired pressure and calling these cells one section
of the battery. Two of these sections placed with the
positive terminals of the sections together and the
negatives together, Figure 36, will give a voltage only-
equal to that of one section, and the two parts are then
connected in multiple or parallel. This method of
conijection is used in some electrical systems that fur-
OdDO
r ^
on
no_
on
no
■gpU
JQHspL
Uq0
r^
Figure 36. — Twelve-Cell Battery of Two Sections for Multiple
Connection. — 1 and +1, Terminals for Left-Hand Section. -+-2
and — 2, Terminals for Rlght-Hand Section. Terminal Marked -h
and — oik Left-Hand Section Is for a Neutral Wire to Provide Six-
Volt Pressure.
nish a high voltage for starting purposes and a lower
voltage for hgnting and battery- charging.
Batteries are in use having three, six, eight, nine,
twelve or fifteen cells and giving respectively six,
twelve, sixteen, eighteen, twenty-four or thirty volts.
All of these except the three-cell type may be divided
into two sections or more. (See Figure 37.) Six-cell
batteries are made to give either twelve volts or else
six and twelve according to their connection. Eight-
cell batteries always are arranged to give eight or
sixteen volts. Nine-cell batteries may give eighteen
volts or may be arranged to give six, twelve and
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STORAGE BATTERIES
77
eighteen volts. Twelve-cell batteries may be arranged
for twelve and twenty-four volts or for six and twen-
ty-four volts. Fifteen-cell batteries are arranged to
give six or thirty volts. The higher voltage is always
used for starting the engine, while the low voltages
are for lighting or for lighting and charging.
The current that a cell will give is measured in
ampere-hours or in watt-hours, generally by the for-
mer. An ampere-hour is the total quantity ,of current
that passes in one hour if the flow is continuous at a
f
f-
Figure 37. — Nine-Cell Battery (Left) with Neutral Terminal, and
Twelve-Cell Battery (Right) Divided Into Four Sections.
rate of one ampere. An ampere-hour will also pass if
a flow of one-half ampere is maintained for two hours
and likewise one ampere-hour will pass if a flow of
two amperes is continued for one-half hour or of four
amperes for a quarter of an hour. The number of
ampere-hours is found by multiplying the number of
amperes flowing by the time in hours that the flow
continues. Batteries are generally rated according to
their ampere-hour capacity, this capacity being based
on discharging the battery in eight hours. A battery
rated as a 120 ampere-hour battery would give a flow
of one ampere for 120 hours, or, theoretically, a flow
of 120 amperes for one hour. This latter flow could
not be secured in practice, however, because of the
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78 STARTING AND LIGHTING
action that would take place in the cells under such
a heavy discharge rate. The 120 ampere-hour battery
should give a flow of fifteen amperes for eight hours,
thus giving its normal output of 120 ampere hours.
At low rates of discharge, that is, with a less number
of amperes flowing, it will be possible to secure more
than 120 ampere-hours, while a high rate will de-
crease the available number of ampere-hours.
Batteries vary in capacity according' to the size
and weight of the plates that are in the cells and
according to the number of plates used. The greater
.the positive plate surface exposed to the liquid in the
cells, the greater will be the ampere-hour capacity of
the cells. Batteries of three cells for automobile use
range in capacity between sixty ampere-hours and
one hundred and eighty ampere-hours, depending on
the lamp and other equipment that must be handled.
Batteries of more than three cells are of less amper-
age in proportion to the increased voltage, although
the watts that may be secured will remain the same
regardless of the combination of voltage and am-
perage used.
The watt-hour capacity may be found from the
ampere-hour capacity by midtiplying this latter figure
by the voltage. One watt-hour is the power secured
from a flow of one ampere under a pressure of one volt
(equalling one watt) for one hour. A six-volt battery
of eighty ampere-hours' capacity would therefore have
a capacity of 480 watt-hours.
BATTERY CHARGE AND DISCHARGE
As previously stated, a charged cell has had its
positive plates changed to peroxide of lead and its
negatives to sponge lead. The liquid in the cells,
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STORAGE BATTERIES 79
which is made from a mixture of sulphuric acid and
water, is called the electrolyte. The peroxide plate,
the sponge plate and the electrolyte make up the work-
ing parts of the cell.
When the battery is connected to the wiring cir-
cuits of the car so that it starts the engine or lights
the lamps, an action immediately begins to take place
in the cells and between the plates and the electro-
lyte. A part of the sulphuric acid in the liquid begins
to combine with the lead in the plates to form lead
sulphate, and the surfaces of both plates are gradually
covered with this sulphate. The percentage of water
in the electrolyte is increased because of the com-
bining of part of the oxygen and the sulphur of the
acid with the lead of the plates, leaving the hydrogen
and oxygen in the form of water, which is a combina-
tion of these two gases. The surfaces of the plates
thus change slowly to lead sulphate, while the liquid
becomes more nearly pure water. When this action
has penetrated a slight distance below the surfaces of
the plates, the coating of sulphate causes the change
to take place at a slower rate, and the battery will then
give a smaller flow in amperes and at a lower voltage.
When the discharge has continued until the normal
output of the battery has been secured, damage will be
done by further discharge, and it will then be neces-
sary to send a charging current through the cells in
a direction the reverse of the flow that takes place
during discharge. The water analogy can be used
here, comparing the battery to a tank that has been
emptied and into which a flow of water must be sent
in a direction the reverse of that taken by the water
that was discharged from the tank.
With the charging current flowing, the sulphate
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80. STARTING AND LIGHTING
of the plates combines with part of the hydrogen .and
oxygen in the liquid to form sulphuric acid. The
positive plate then becomes pero^de of lead and the
negative is left as sponge lead. This transformation
continues until the sulphate is completely reduced,
and the battery is then said to be charged. Further
flow of current will not, increase the charge nor the
flow that may be drawn from the battery on dis-
charge. It should be understood that the sulphate
referred to here is not the injurious form that attacks
the plates when they are said to be **sulphated," as
a disease or trouble. Plates that are **sulphated,'*
in the latter sense, are over-sulphated, and tbe deposit
is then an almost pure and practically insoluble lead
sulphate that prevents proper action in the cells.
The rate of flow through the battery while being
charged depends on the ampere-hour capacity of the
battery, and should never exceed a number of amperes
equal to one-eighth of this capacity. That is, an
eighty ampere-hour battery should not be charged
at a rate in excess of ten amperes, or one-eighth of
the total capacity.
The efficiency of a battery is greater with low rates
of chaise and discharge than with high rates. By
efficiency is meant the proportion of current that may
be withdrawn from a battery in comparison with
the amount sent in on charge. The conditions of use
on an automobile are favorable from an efficiency
standpoint in some ways, although the conditions are
hard on the battery in others. The action on the car
is to give some charge while the dynamo runs and then
some discharge as the lamps bum. Oftentimes the
battery will be required to absorb the excess of dynamo
output above the current being taken for the lamps,
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STORAGE BATTERIES 81
and at other times the battery will be called upon
to make up a slight deficiency between the lamp load
and dynamo output. This use of the battery is
called ''floating" it in the lines, and it is known that
the efficiencies of floating batteries are higher than
for those that are completely charged and then com-
pletely discharged.
The rate of discharge should not exceed in amperes
one-eighth of the ampere-hour capacity of the battery,
although rapid discharge is not very harmful to a
battery provided it is not then allowed to stand in a
discharged condition. The efficiency of the battery,
if caUed one hundred per cent at a discharge rate of
one-eighth of its capacity, drops with increase of dis-
charge amperage until at one-sixth of the ampere-
hour capacity the efficiency is about nine-tenths. At
double the eight-hour rate, or one-fourth of the total
capacity, the efficiency is about four-fifths, while a
discharge that would empty the battery in one hour
will allow less than half of the normal number of
ampere-hours to be secured.
The greatest care that is necessary in allowing a
battery to discharge is to see that it does not do. so
to such a point that the voltage becomes abnormally
low. Under no conditions should discharge be con-
tinued when the voltage is 1.7 per cell, and if the
current flow from the battery is carried past this point
serious damage will result from over-sulphation on
the plates, distortion and warping of the piates, and
the formation of harmful corrosion on the metal of
the grids.
The proper charging rate for the different batteries
may be found from the information given on the
nameplate attached to the battery case. In most
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82 STARTING AND LIGHTING
cases two different rates will be given, one marked
* ' start, ' ' and the other ' ' finish, " or ' * 24-hour. ' ' The
starting rate is the greatest that the battery will
stand, and should be as great as the highest rate of
charge that the dynamo can send through the battery.
The finish rate is used when the battery is charged
from an outside source of current other than the car's
dynamo. The high rate is between one-sixth and one-
tenth of the capacity in ampere-hours^ generally about
one-eighth. The finish rate is approximately one-
fourth to one-half of the high rate, generally about
one-third.
When it is necessary to charge a battery from an
outside source, it must be remembered that the posi-
tive side of the charging current must be attached to
the positive terminal of the battery and the negative
of the charging current to the negative of the battery.
The polarity of any wires may be determined by im-
mersing their ends in water to which has been added
a small amount of acid or salt. The wire that comes
from the negative side of the source will bubble most.
The charging current must always be direct cur-
rent. Alternating current connected directly to the
battery without the use of a rectifier will not only fail
to charge the battery, but will do positive damage.
Direct current is abbreviated, D. C, and alternating
Current, A. C. It will be necessary to ascertain which
kind of current is supplied by the charging circuit to
be used, and if it is alternating, a rectifier must be
inserted between source of current and the battery
to be charged.
With a supply of direct current at hand, the battery
may be charged by inserting such a resistance in the
line as will allow the proper amperage to flow through
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STORAGE BATTERIES
83
the cells. The high voltages found on lighting and
power circuits in buildings would send a damaging
flow through the cells, and it will always be necessary
to use incandescent lamps or other forms of resistance
with such current and voltage. (See Figure 38.)
S5 amp ComBioed Swilch ood
js^ Plug Cui-oo). (20 Amp Toaetf)
1)4? Cohooi (20 Afop. FvBt6)y
^Conpe<iiog>8 f6t Cborgxpg hoHtt^its
Figure 38. — Battery Charging with Lamps for Resistance.
A sufficient number of incandescent lamps may be
lighted at one time to allow the amperage to flow at
the rate marked * * flnish, " or ' * 24-hour. ' ' If the lamps
to be used are marked on their bulbs with the number
of watts required, as is usually the case, enough lamps
must be lighted to give a total number of watts when
added together that will allow the proper amperage
to flow. The amperage desired should be multiplied
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84 STARTING AND LIGHTING
by the voltage of the charging line, this giving the
number of watts requireiL Enough lamps must then
he used to make up this number of watts. Thus, if
the battery requires three amperes charge and the
charging current is 110 volts, three times this voltage
gives 330 watts as the result. Seven 50-watt bulbs
wiU make 350 watts, which will be just about right.
If the lamp bulbs are marked in candlepower, their
wattage may be found by multiplying the candle-
power by three for carbon filament bulbs, or consider-
ing a 16 c. p. bulb as a 50-watt bulb and a 32 c. p.
bulb as a 100-watt bulb, etc. If tungsten lamps must
be used, the candlepower and wattage are equal, that
is, a fifty-candlepower bulb is a fifty-watt bulb.
A battery should have each cell filled with pure
water until the level is above the tops of the plates
before any charging is done; this applies whether the
battery is charged on the car or from an outside
source. When giving an outside charge it is desirable
that the current should flow without interruption
until the charge is complete.
ELECTROLYTE AND TESTING
From' the explanation given of the action that takes
place during charge and discharge, it will be seen that
the proportion of acid in the electrolyte will ^ve an
indication of the condition of the battery, that is,
whether it is properly charged or nearly discharged.
The acid is much heavier than water, and as the
proportion of acid in the liquid becomes greater, the
weight of the electrolyte becomes greater. Therefore,
the heavier the electrolyte, the more nearly charged
the battery is known to be.
To find the condition of the battery by testing the
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STORAGE BATTERIES
85
liquid, a hydrometer is used. The hydrometer (Fig-
ure 39) is a glass tube having a hollow bulb and a
weight at one end and a thin tube with a numbered
scale at the other end. When this instrument is
I "I
Figure 39. — Hydrometer Syringe and Hydrometer.
allowed to float in the liquid from the battery cells,
the point on the scale to which it sinks indicates the
weight of the liquid, because, of course, the hydrom-
eter will not sink so deep into the heavy liquid with
a large proportion of acid as it will into the liquid
when almost all water. The scale is graduated accord-
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bo STARTING AND LIGHTING
ing to the weight of liquids, known as specific gravity,
which is their weight compared to that of pure water.
On the stem of the hydrometer appear numbers from
1.100, near the top, to 1.300, near the bottom. With
the battery fully charged the hydrometer will sink
only to the point marked 1.300, or somewhere near
that point; but with a discharged battery whose elec-
trolyte is mostly water the hydrometer will sink to
the 1.100 mark. Different degrees of chaise are indi-
cated by the hydrometer's sinking to points on the
scale intermediate between the 1.100 and the 1.300
marks. The point indicated at the surface of the
liquid is the specific gravity of the electrolyte. If
the scale were long enough and the instrument placed
in pure water, it would sink to the point marked 1.000,
which is the basis of the scale. If the instrument
were then placed in the kind of pure sulphuric acid
used in batteries it would sink to about 1.835, which
is the specific gravity of the acid generally used.
The hydrometer itself is usually carried in a larger
tube with a small nozzle at its lower end that may be
inserted into the cells, and with a bulb at the upper
end so that some of the electrolyte may be drawn
from each of the cells for purposes of test. In the
top of each cell of every battery will be seen a small
plug. This plug may be unscrewed or released from
its lock and will leave an opening exposed that passes
into the interior of the cell and through which the
electrolyte may be seen, or the tops of the plates if
the liquid is low enough. With the plugs removed,
the hydrometer syringe, as the tube and bulb is called,
may be inserted into the cell, and when the bulb is
squeezed and allowed to expand some of the liquid
wiU be drawn up into the tube and the hydrometer
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STORAGE BATTERIES
87
will float in this liquid. (See Figure 40.) After all
pressure has been released from the bulb the specific
gravity of that liquid may be noted on the hydrom-
eter scale at the point where the instrument rises
above the surface of the electrolyte. The gravity
^3
„,,, ..mw '!:l^pu ^
Figure 40. — Hydrometer Floating in Liquid Drawn Up Into Syri ge.
should then be noted and the liquid
to the same cell from which it was
method should be used to find the
each cell.
If this gravity is between 1.250
is well charged. If the gravity is
1.250, the cell is at least half, but
Gravity between 1.150 and 1.200
carefully retun/ed
drawn. The same
specific gravity of
and 1.310, the cell
between 1.200 and
not fully, charged,
indicates that the
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88 STARTING AND LIGHTING •
cell is nearly discharged, while gravity of 1.150 or
below means that the cell is discharged to a point
at which no further discharge should be allowed. The
gravity is often mentioned in ** points," the diflference
between 1.200 and 1.250 being 50 points.
The specific gravity should not be tested until after
the battery has ^been charged, should the water be
found so low that it' is necessary to add more to bring
the liquid above the plates. If the battery is in good
condition, the gravity will be within twenty-five points
of the same in all cells. If there is a greater diflference
than this it usually indicates trouble in the cell or
cells that are low. When, near the end of a charge,
the specific gravity of the liquid in a ceU does not
show any increase for two hours or for three readings
taken one hour apart, the cell is fully charged.. At
this time bubbles of gas should be rising through the
electrolyte and showing freely on the surface.
BATTERY CARE
It is very essential that the storage battery have
certain attention at regular intervals. The most
important item in the care of a battery is that of
adding pure water to each cell at least once each week
during warm weather and at least every second week
in cold weather while the car is in use. The water is
added through the holes left with the vent plugs
removed and may be easily handled by using the
hydrometer syringe. A sufficient quantity of water
should be placed in each cell to bring the surface of
the liquid from one-quarter to one-half inch above
the tops of the plates, this point being indicated in
most cases by a rim that can easily be seen at the bot-
tom of the hole with the plug removed.
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STORAGB BATTERIES 89
The "water used for this purpose must be distilled
or else perfectly clean rain water. Tap water or water
that has been kept in metal containers must never be
used. Some city waters may be used, but it will
always be necessary to make an analysis before their
safety can be determined. Except when some of the
electrolyte has been spilled from one of the cells,
nothing but pure water should ever be added. In no
case should undiluted sulphuric acid be used. If it
is known that a part of the electrolyte has been lost
through other means than by evaporation and the
slight spray from gassing, the level may be brought
up in the low ceU by testing the gravity in the adjoin-
ing ceUs and then making enough electrolyte of this
gravity to bring the level in the low cell to the required
point.
Electrolyte is made by slowly pouring chemically
pure sulphuric acid into distilled water until a mix-
ture of the desired gravity is reached. Two and one-
half parts of water to one of acid will make a mixture
of about 1.300 specific gravity. Lower gravity is
secured by adding more water. The mixture must be
allowed to cool before it is added to the cell. If the
water is poured into the acid, a violent action and
throwing of liquid will take place.
The specific gravity of each cell of the battery
should be taken at regular intervals, and if the whole
battery is getting lower the fault should be looked'
for without delay. If one cell becomes lower, but the
others remain normal, trouble in that cell is indicated.
Care should be used when testing not to spiU electro-
lyte on top of the battery, as it will cause corrosion
at the terminals and partial short-circuiting of the
cells" If it is found that one cell always takes more
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90 STARTING AND LIGHTING
water than others, it is probable that the jar for that
cell has become broken. The level of the liquid in
the cells should not be above a point one-quarter to
half an inch above the tops of the plates, because
during charge the gassing that occurs will cause the
electrolyte to overflow and cause damage outside of
the cells.
At the time of testing or adding water to the bat-
tery, the terminals should be carefully examined for
looseness or breakage, either at the connecting bars
between the cells or at screwed or tapered connectors.
No copper wires should ever be attached at the lead
battery posts, as they will soon be eaten away by the
action of the acid. Should the connections be found
covered with corrosion or verdigris, t^iey should be
washed with ammonia water, and in any case should
be covered with a coat of vaseline to prevent such
action by the acid.
The battery must be firmly secured in its box so
that movement from the motion of the car is impos-
sible. Wood cleats should be placed under the bat-
tery and fastened into the bottom of the box. The
space all around the battery and on top should be free
and open for the circulation of air. The best method
of holding the battery is by using hooked bolts that
catch on the battery handles and screw down tight.
If the battery case is wet or if the inside of the bat-
tery box is wet, the moisture should be wiped away
with a cloth slightly wet with ammonia water.
It is, of course, essential that the electrical condi-
tions of charge and discharge be correct for the
battery. These points are taken up in other parts of
this book, but it should be noted that the dynamo
should give such an output at fifteen miles an hour
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STORAGE BATTERIES 91
car speed that the battery is not being discharged with
all lamps turned on. It should also be remembered
that the demands on the system and on the battery
are much greater in winter than in summer. The
efficiency of the battery is much lower when cold than
when warm, and the dynamo does not give an output
as great as would be required for the extra lamp load
imposed by the greater number of dark hours, and
also by starting a cold engine under winter condi-
tions. Therefore, the battery should have the very
best of care during cold weather. Lamps should be
used as economically as possible, and, if convenient,
lower candlepower bulbs should be substituted in the
lamps. The engine should be started by hand for
the first time on cold mornings, and at all times
the carburetor and ignition should be in such adjust-
ment and condition that but a very few seconds*
cranking with the motor will suffice to start the
engine. Care of this kind will do more than anything
else to insure satisfactory operation of the whole elec-
trical system, because nothing else can do its work
unless the battery is in good order and properly
charged.
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CHAPTER IV
LAMPS AND WIEING'
One of the principal purposes of the whole electrical
system is to furnish light, and the subject of lamps
and their connections is an important one. The light-
ing parts that are most directly concerned are the
bulbs and reflectors in the lamps, the wiring with its
insulation and supports, the switches for turning the
lamps on and off, and, in some Cases, the protective
devices, such as fuses and circuit breakers.
THE LAMPS
Bulbs. — ^A bulb is composed of a filament enclosed
in a glass housing from which the air has been almost
completely exhausted, and this glass part is carried
on the metal base (Figure 41). Two kinds of filament
are in use, tungsten and carbon, and two kinds of
bulbs, one in which the exhausted air is not replaced,
and another in which the air is replaced with nitrogen
gas. The first kind of bulb is known as the vacuum
type, the second is called a nitrogen bulb.
Tungsten filaments should be used exclusively be-
cause of their greater efficiency as compared with
carbon. Depending on the candlepower, the tungsten
filament will require from 0.95 watts for each candle-
power up to 1.25, while the carbon bulb will take on
an average of 2.5 watts for each candlepower of light.
It is, therefore, poor economy to T;ise carbon filament
92
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^AMPS AND WIRING
93
bulbs for any piirp9se. In making lamp calculations
the following data may be used :
Bulbs up to 4 c.p.. . .1.2 watts per candlepower
6 c. p. to 10 c. p. .... . 1.0 watts per candlepower
12 c.p: and above 95 watts per candlepower
Bulbs operating at their normal voltage will require
an amperage sufficient to allow the specified consump-
Flgure 41. — Double-Contact and Single-Contact Lamp Bases.
tion in watts. This will cause the bulb to give its
full candlepower, and its useful life may be expected
to reach from 200 to 300 hours of burning. If the
voltage is less than normal, the bulb will not require
its rated flow in amperes, and under these conditions
the candlepower will be lower and the life longer.
Bulbs in common use range in voltage from 3 or
314 up to 21, depending on the number of cells in
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94 STARTING AND LIGHTING
the battery with which they are used and their con-
nection with each other. It is customary to use bulbs
of a voltage one-sixth above what would be required
on a basis of exactly two volts for each cell of the
battery. Thus, with a three-cell battery, seven-volt
bulbs will be used in place of six ; with a twelve-volt
battery, fourteen-volt bulbs will be used, while with
-an eighteen-volt battery, twenty-one-volt bulbs will
be found. The three-volt bulbs are used in pairs
on a six-volt battery, the two three-volt bulbs using
the six volts of the battery just as one six-volt bulb
would do.
^Five bulb sizes are in use. The bulb size refers
to the diameter through the glass part, and does not
vary exactly according to the candlepower. Two,
four and sometimes six candlepower bulbs are made
of three-quarter inch diameter. Four, six and some-
times eight candlepower bulbs are one inch or one
and one-quarter inches. Bulbs of lai^r candle-
powers are made either one and one-half or two and
one-sixteenth inches in diameter. In replacing old or
broken bulbs with new ones, the replacement should
be made with a bulb of the same diameter as the one
removed, otherwise it will be necessary to refocus the
lamp, and if too great a change is made in the size
the refocusing cannot be done properly.
Bulh Bases and Sockets, — Four types of bulb base
are in use ; two, of the familiar screw type, are seldom
found except in interior body work, while the other
two, of the bayonet type, are in common use for all
purposes. The bayonet type is often called the
Ediswan socket, and makes use of a spring locking
device that holds the bulb firmly in place against
jarring and consequent loosening. (See Figure 9.)
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LAMPS AND WIRING 95
The base for this type is cylindrical and carries two*
small projecting pins on the sides and directly oppo-
site each other. The socket into which the base fits
is also cylindrical, and of such proportions as to make
a rather loose fit. Two slots are cut along the sides
of the socket, and when the bulb base is placed in
position, the projecting pins slide, into these slots.
At the bottom, the slots end in a small upturned notch
so that the base pins will fit into the notches when
the bulb is given a part of a turn. In the bottom of
the socket are springs that press against the inner end
of the base and keep the pins in place in the notches.
One kind of bayonet base carries a single electrical
contact in the center of the bottom of the base, this
contact coming against a contact spring or plunger in
the socket when the bulb is in place. The current for
the lamp is carried through the contact for one* side
of the circuit, while the connection for the other side
of the circuit is completed through the metal of the
base cylinder where it comes in contact with the metal
of the socket. This is called a single contact base,
and was primarily designed for use with the one-wire
or grounded system of wiring in which the shell of
the socket is attached to the metal of the car to carry
the current for one side of the circuit.
Another kind of bayonet base has two contact points
on the bottom of the bulb, both being insulated from
the metal of the socket and from each other. The
current for the lamp is carried in through one contact
and out through the other, and there are two springs
or plungers in the socket that make connection with
the base contacts when the bulb is in place. This is
called the double-contact base, and is used with the
two-wire, or insulated return method of car wiring,
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96 STARTING AND LIGHTING
in which both sides of the circuit are carried by insa-
lated wire.
One of the screw types is called the candelabra
base, and the other one, which is of smaller size, is
called the miniature base. Their construction is sim-
ilar to that used for house lighting work, a single
contact carried in the center of the bottom of tiie
base making connection with a spring in the bottom
of the socket. The other side of the circuit is com-
pleted through the shell of the socket and of the base.
Lamp Care. — The light from the bulbs is directed
toward the road by means of silver plated reflectors
of parabolic shape or by reflectors made from silvered
glass like a mirror. The glass reflectors are not found
as commonly as the silvered metal ones, but give
satisfactory service when used.
In order to reach the interior of the lamp for bulb
renewal, cleaning or focusing, it is necessary to remove
or swing to one side the glass cover placed over the
front of the lamp. This cover may be held in place
by hinges, although plain hinges are seldom used
because the lamp should never be opened except when
really necessary, and because of the danger ihat the
bulbs will be taken out if left too easily accessible.
Lamps are often made with pinned hinge joints on
both sides, and it is then necessary to withdraw either
one of the pins to allow the other side to act as a
hinge. ^
The lamp covers or glasses are often held in place
by screws and in some cases the screw-heads are made
so that it is necessary to use a peculiar form of wrench
that is furnished with the tool equipment of the car.
A type of lamp in rather common use holds the fronts
in place by means of a spring lock, and with the cover
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lAMPS AND WIRING 97
in position nothing about the outside of the lamp
gives any indication as to the method of fastening.
This type is handled by pressing in on the rim of the
cover and at the same time turning it to the left, when
the whole front of the lamp will come oflP. Great care
should be used to prevent dirt or moisture from
touching the reflector while the cover is removed.
Should the reflectors become dirty or tarnished,
they may be carefully cleaned and brightened, al-
though the surface of the reflector will be somewhat
Figure 42. — Method of Cleaning Lamp Reflectors.
damaged every time it is touched, no matter how care-
ful the work is done. Dust may be removed from the
reflectors by blowing it out or, if it does not yield V>
this treatment, a stream of clean cold water at very
low pressure may be used* If water is used the re-
flectors must be allowed to dry by the air alone, and
must not be wiped off.
For cleaning the silvered surface no liquid except
alcohol is ever used. This is applied with a clean,
soft chamois skin. The chamois must be held so
that there are no wrinkles, and the reflector is then
wiped over the whole surface by using a rotary
motion (Figure 42), starting at the bulb socket and
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98
STARTING AND LIGHTING
gradually working out toward the front of the lamp.
The cleaning is sometimes done by wiping from front
to back, but in either case the pressure should be very
light and even. Rubbing back and forth will surely
scratch the surface of the reflector.
Figure 43. — Lamp Focusing Methods. 1 — ^Light Rays Follow
Lines A. with Proper Focus; with Improper Adjustment They Fol-
low Lines B or (7. 2 — Focusing Screw at Upper Front Edge of
Reflector. 3 — Focusing Screw at Rear of Lamp Case. 4 — Adjust-
ing Screw in Lamp Socket.
If the silvered surface is tarnished it may be pol-
ished by moistening the chamois with alcohol and then
applying a small quantity of jeweler's rouge. The
wiping should then be done in the same way as for
cleaning. After the coating of oxide has been re-
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LAMPS AND WIRING 99
moved, the polish is completed with more rouge placed
on a dry chamois skin.
In order that the lamps may be used to the best
advantage, the bulbs must be properly focused and
the lamps must be^in such a position on their brackets
that the rays of light are thrown on the road at the
proper point. It will generally be best to get the
bulbs in approximately proper focus and then place
the lamps in proper alignment.
The bulbs are focused by moving them forward or
back in the case so that their filaments will come into
a different relation to the curved surface of the reflec-
tor. (See Figure 43.) Many lamps are made so that
the bulb position may be changed by turning a smaU.
screwhead or nut that will be exposed when the front
of the lamp is out of the way. The focusing screw is
usually in the center of the upper edge of the rim, and
by turning it one way or the other, the bulb is moved
forward and back. Bulbs are also held in a socket
that may be slid bodily in or out of the reflector by
first turning it slightly. When the bulb and socket
have been moved to the desired position, the socket
will lock in place when released. Other lamps hold
the socket in a cylindrical casing and lock it in place
with a clamp or setscrew. This screw can be
reached from the rear side of the reflector, and with
it loosened, the socket may be pushed back and forth.
One lamp should be focused at a time. This may be
done by turning the current off from one of them or
by covering one with a thick cloth or coat. The
focusing must be done in a dark room or on a dark
road, preferably on the road. The car should be
placed so that no street lights are near enough to
cast a light near the car, because they will giffect the
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100 STARTING AND LIGHTING
adjustment. The bulb should be moved back and
forth untU the light on the road is clean and free from
rings or black spots. If the work is done in a room,
the light may be directed against a wall and the bulb
moved until a clean and clear ring of light is thrown
straight ahead. It will always be best to drive the
car on the road before deciding that the adjustments
are correct. It will often be found that focusing
which is apparently right with the car standing still
will not be the best that may be secured for driving.
After each of the lamps has been focused as de-
scribed, the fronts should be replaced and the lajnp
casings moved on their brackets, or the brackets them-
selves moved so that the light from each lamp strikes
the road at the point desired by the driver. The best
method of changing the lamp position will be appar-
ent upon examination. Some cars are provided with
adjustments for this purpose and others have no
means except to bend the brackets.
WIRING
This subject immediately suggests the two prin-
cipal systems that are used for carrying the positive
and negative sides of the circuits, that is, the one-
wire, or grounded return, method, and the two-wire,
or insulated return, method. The wiring applies as
much to the chai^ng system as to the lighting, and
the information that follows will take both systems
into account.
One-Wire System. — This construction makes use of
the fact that the metal of which the chassis parts are
made is an excellent conductor, and because of the
large sectional areas in use as compared to the sizes
of wire, ia conductor of very low electrical resistance.
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LAMPS AND WIRING
101
In place of the older method of carrying both sides
of the circuits through copper wires insulated from
metal parts of the car, the one-wire system at-
taches one side of the battery, one side of the lamps
and one side of each of the other electrical units
included, to the frame, or to other metal parts of
the car that are in electrical contact with the frame.
(See Figure 44.) From the remaining side of the
battery wires are run through the switches and other
connecting parts to the lamps and whatever other
units are included in the one-wire system. Any part
h
t^
^
^
Figure 44. — One -Wire Connections,
that is thus attached to the metal of the car parts is
said to be grounded, and this system is oftentimes
called the ground return system.
Theoretically it would be possible to eliminate one-
half of the wire that would be require'i with a two-
wire system, but this is not true in practice, because
it is not possible to place the battery, dynamo and
other units in such a way that they may always be
attached directly to the metal work, or to 'Aground.''
This is especially true of body lights and of side and
dash lamps that are carried on wooden parts of the
car. The saving from the standpoint of wire used is
in practice between one-third and one-half, the exact
amount depending on the design and mountings used.
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102
STARTING AND LIGHTING
The principal advantage of the one-wire system,
outside of the evident advantage of saving in wire,
is the greater ease of jproviding heavier insulation.
It will be realized that, in a lamp socket and bulb
base, for instance, the room that may be utilized is
quite limited, and if but one conductor must be insu-
lated, the covering and protection for this one side
of the circuit may be made heavier than wjere it
necessary to handle two insulated leads for each lamp.
The same advantage applies in a similar way to the
other units, and because of the saving in material
MJ
rf
Figure 45. — Two- Wire Connections.
and the greater ease of manufacture and installation,
the one-wire system has gained steadily at the expense
of the two-wire system since its first adoption.
Care must be used with this system of wiring to
see that the connections of the copper wires from the
various units are securely fastened to the metal of the
car and that the contact surfaces are perfectly clean
and protected from the action of air and moisture.
Two-Wire System. — This method of wiring does
not make use of the metal work of the car as a con-
ductor, both sides of the circuit being carried by insu-
lated copper cables at all points (Figure 45). The
most apparent advantage of this method is in the
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LAMPS AND WIRING 103
lessened danger of accidental * short oircuits from
broken insulation. With both positive and negative
conductors insulated it would be necessary to break
through the insulation on both sides before any leak-
age of current could take place. Even though the
positive wires were bared, no current could flow from
positive to negative sides of the battery unless the
negative lines were also bared at a point that would
allow contact between positive and negative. Like-
wise, the negative cables, might be stripped of their
insulation at one or more points without leakage
occurring unless the positives were also stripped at
the points that would touch the negatives.
With the one-wire system: either the positive or
negative side, depending on which one is grounded,
will always be without insulation, and a failure of
the insulation on the other side of the circuit at any
point where the cable can come into contact with the
metal parts of the car will result in a short circuit.
This may be guarded against to a certain extent by
the heavier insulation possible with the one-wire
fifystem.
Because of the possibility of short circuits with the
one-wire method, it is customary to use fuses that
will bum out or circuit breakers that wiU open with
an abnormal flow of current through the wires. By
thus breaking the circuit in trouble, the danger of
completely discharging the battery is eliminated.
With the two-wire system fuses and circuit breakers
are not so commonly used, although their adoption or
omission depends entirely on the ideas of the
designer.
Another advantage of the two-wire system is found
in the absence of connections between copper con-
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104
STARTING AND LIGHTING
ductors and the steel or aluminum of the motal parts
of the car. This form of joint is not as easy to make
and is not of such low resistance as one between cop-
per and copper. Any joint between two* different
metals is subject to an electrical action that will result
in corrosion and high resistance unless the joint is
properly protected. The grounding connections be-
tween the lamps and their brackets and between the
Figure 46. — Three- Wire System with Evenly Divided Battery.
electrical parts mounted on the engine and the metal
of the engine must be well made and carefully watched
to avoid looseness and dirty contacts with the one- wire
system, while the two-wire method requires only that
the joints be clean and tight between surfaces that
are both copper.
Three-Wire System. — This class of wiring desig-
nates a method by which two different voltages may
be secured on two diflferefnt circuits with the use of
but three wires for both circuits in place of four, as
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LAMPS AND WIRING 105
would ordinarily be required. It may be used with
either the grounded or insulated return wii^es, inas-
much as it really means three conductors, which may
be of wire or pf the metal of the car parts.
The connections for one kind of three- wire system
are shown in Figure 46. The battery is composed of
two separate sections, A and B, which, for purposes
of illustration, may be considered as of six volts each.
The two sections are connected at their terminals,
X and T, X being negative and T positive. The
remaining terminals are shown at P and N, P being
positive and N negative. Between the terminals P
and N twelve volts may be secured, inasmuch as both
sections are working together and adding their pres-
sures. The head lamps are connected so that each
bulb is attached to battery terminal P and to N, and
they will therefore operate at twelve volts pressure.
The side lamps are connected in such a way that
the left-hand lamp is attached between positive ter-
minal P and negative terminal X, using one section
of the battery and six volts' pressure. The right-
hand side lamp is attached between the negative ter-
minal N and the positive terminal Y on the other
section of the battery, and also at six volts pressure.
The terminal formed by joining X and Y is called
the neutral terminal, and the wire C is called the
neutral wire.
It will be seen that the removal of the wire C would
leave the two side lamps in series with each other,
so that all the current passing through one of them
would also have to pass through the other. With
the wire C removed, the two lamps would be connected
in series between the battery terminals P and N,
and would receive twelve volts. Two six-volt lamps
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106
STARTING AND LIGHTING
will operate on a twelve-volt circuit when connected
in seriesi, and this rule holds true for any combination
of voltages in which the battery or circuit voltage is
equal to the number of lamps multiplied by the
voltage of each lamp. The lamps must all be of the
same voltage, and this method would not always oper-r
ate with one six-volt and one twelve-volt lamp on an
eighteen-volt circuit.
^
^
Sf0
Motoi
Figure 47. — Three- Wire System with Two-Lamp Voltages and Higher
Voltage for Starting Motor.
The advantage of the neutral wire C, in this case,
would be that either one of the side lamps could be
operated independently of the other by allowing the
neutral wire to carry the side lamp current. With
both lamps turned on, the neutral wire is dead, and
the current flows from battery terminal P to ter-
minal N.
Another three-wire arrangement is shown in Fig-
ure 47. In this case the battery is divided into two
sections of unequal size, section A being six cells of
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LAMPS AND WIRING 107
twelve volts, and section B of three cells and six volts.
The sections are connected with each other between
terminals X and Y. This arrangement allows* of three
different voltages. The starting motor is connected
between the terminals P and N, and receives the full
voltage of both sections, which will be eighteen.. The
head lamps are connected between the positive ter-
minal P and the negative terminal X, and therefore
operate with twelve vplts from the battery section A.
The side lamps are connected between the negative
terminal N and the positive terminal Y, and there-
fore operate at six volts on the battery section B,
The wire C is in this case neutral and acts for either
the side or head lamp circuit. Were the wire C to
be removed from Figure 47, it would leave the twelve-
volt head lamps in series with the six-volt side lamps
on an eighteen-volt battery. As stated before, this
should not be done, because, except under one condi-
tion, either the head lamps or the side lamps would not
bum. The one condition under which both sets would
bum with the neutral wire removed is with both sets
of such candlepower that they would require exactly
the same amperage to light them. With lamps in
series, the flow or amperage is the same through all
parts of the circuit, and* the set that takes the least
amperage will govern the flow through the circuit,
with the result that the lamps that require a greater
flow will not light up at all, or but dimly.
Wires. — The wires may be considered as consisting
of the copper which forms the conductor for the cur-
rent, of the insulation covering the conductor, and of
the terminal connections that serve to make the nec-
essary attachments between the various wires and
between the wires and the electrical units on the car.
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108 STARTING AND LIGHTING
Of the three parts, the last will be found most impor-
tant from the standpoint of upkeep. The greatest
trouble is experienced in making and keeping the
terminal connections tight and clean at all times.
Unfortunately it is not possible to make permanent
connections, because of the necessity that may arise
for removing some of the wiring or some of the in-
struments. It will, therefore,^ be necessary to use
the greatest care at this point if trouble is to be
avoided.
The size of conductor that should be used at any
particular point in the installation depends on the
amperage and voltage that is to be carried and on the
length that the current must be taken between the
units. Conductors are usually measured by wire
gauge sizes, in which the larger numbers indicate the
small sizes of wire, while low numbers indicate large
sizes of wire. Gauge sizes (Brown & Sharpe stand-
ard) are foundfrom No. 16 (about one-twentieth inch
in diameter) to No. 00 (nearly three-eighths inch in
diameter). Sizes from No. 3 up to No. 00 are used
for the starting circuits, while sizes from No. 8 to
No. 16 are for lighting and charging circuits. Should
the wire size be too small for the work it is called
upon to do, the resistance will be so great as to cause
an abnormal drop in voltage and improper operation
of the units supplied by the defective circuit.
The insulation of the wire is oftentimes called upon
to do double duty in giving protection against leak-
age of the current, and also in protecting the con-
ductor against mechanical injury. Electrical protec-
tion is usually cared for by various compounds of
rubber that surround the conductor with a protective
coating of sufficient thickness to resist the voltage in
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LAMPS AND WIRING 109
use plus a liberal margin for safety. Various means
are used to give mechanical protection, the commonest
being a covering of fabric woven or braided over the
electrical insulation of the wire. In many installa-
tions the mechanical protection is given by covering
the wire with a flexible housing of braided brass or
very thin steel. This type is called armored cable,
and gives excellent results in use.
The wiring should be firmly fastened to the parts
of the car near which it runs, and these fastenings
should be made with screwed joints of some form.
The wires should never be fastened in such a way that
the covering will come into contact with comers or
sharp edges of metal, because the final result will be
breakage or short circuits. In case it is necessary
to run the wiring into positions where it will be
exposed to the possible action of grease, oil or water,
it should have a weatherproof coating of some form.
If armored cable is not used it is general practice to
use metal tubing of flexible construction, or else to
use conduit. Should neither of these protecting
coverings be supplied, the needed protection may be
given by covering the exposed portion of the wiring
with ordinary circular loom, such as is used in sta-
tionary electrical construction.
No wire should be used that is not designed for
starting, lighting or ignition work. This means that
the conductor must be composed of a cable made up
from a large number of flne wire strands and known
as flexible or stranded cable. The insulation must be
designed for this class of work, and under no condi-
tions is it permissible to use substitutes like flexible
lamp cord, such as is found in house wiring.
All wire ends should be fitted with metal terminals
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110 STARTING AND LIGHTING
(Figure 48) of special form; designed to make a good
electrical and mechanical connection with the various
units. These terminals should always be soldered to
the ends of the wire so that there is no chance of cor-
rosion or looseness. In case it is necessary to attach
a wire and n© terminal can be fitted, the work may be
done by baring the end for a short distance and, after
bending the end into a loop, dipping it into solder so
that it is made solid enough to prevent loose strands
from forming. The loop should then be placed on its
connection in such position that it wraps around in
a right-hand direction, and so that tightening of the
Figure 48. — Wire Terminals.
screws will tend to coil the wire closer around the
terminal post in place of unwrapping it.
After wiring has been attached to the terminal
posts, the fastening screws should be made tight and
should preferably be locked in position with wire or
by soldering. While this method makes it harder to
remove the parts, it also prevents the commonest of
all troubles, looseness.
SWITCHES
The amperage or current that is carried by the
circuits of the automobile lighting system is consid-
erably greater than that carried in the ordinary house
lighting system. The amount of light in candlepower
may be no greater or it may be about the same. This
would mean that the power in watts would be about
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LAMPS AND WIRING 111
the same, and because of the low voltages in use with
car lighting systems, the amperage must be corre-
spondingly higher. The contact surfaces of lighting
switches for use on cars must be made large and of
material that will stand the sparks that are formed
when the circuits are broken.
Many types of separate lighting switches are in
common use. One of these types carries two small
push-buttons on its face-plate, one button serving to
close the circuit and the other to open it. They are
mounted at opposite ends of a pivoted arm so that
pushing one of them in will cause the other one to
come out. The contacts are actuated by spring-
operated arms so that the circuit is* broken quickly
enough to prevent excessive arcing. Another type
very similar in construction makes use of but one
button, this usually being pulled out to close the
circuit and turn on the lights and pushed in to turn
them off. One switch is provided for each circuit
that is to be controlled, and the switches are usually
assembled with the proper number attached to one
faceplate that appears within reach of the driver.
A third type is that known as the rotary snap
switch (Figure 49). This is built on the same prin-
ciple as the switches in common use for house light-
ing, with which the switch button is always turned to
the right to turn the lamps off if they are burning
and to turn them on if they are unlighted. These
switches for automobile work are made so that the
several combinations of lights are given by successive
quarter turns or sixth turns of the button. A combi-
nation in common use for the four quarters would
be as follows: All Off. Head Lights Dim, Tail
Light Bright. All Lights Bright. Side Lights and
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112
STARTING AND LIGHTING
Tail Light On. The next quarter would then bring
the switch back to the **A11 Off'' position.
Many combination switches are in use that care for
the lighting, starting and ignition circuits by bringing
two of them or all three to the one-switch unit. The
combination switch that serves for lighting and igni-
tion is in most common use, this type usually being
fitted with separate buttons or levers for the two
functions. This makes it in reality two switches of
-^C7
<50
Figure 49. — Rotary Lighting Switch Construction.
any suitable form carried in one housing. Switches
are also in use that have but one lever or button for
both lighting and ignition. With the switch button
in place, the ignition is turned on, and with the button
moved into various positions the different lighting
combinations are secured. Removal of the button
with any lighting combination in use will then stop
the ignition, but will allow the lights to remain
lighted as with the button in place.
Combined starting and ignition switches are in gen-
eral use with motor-dynamos that do not make use of
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LAMPS AND WIRING 113
an .automatic ciit-out. (See Figures 59 and 60.)
These switches usually have three positions, although
they are also made with but two changes, **0n'' and
'*Off/' With the three-position switch the points are
marked ''Off,^' ''NeutraP' or ^^dle,'' and '^Start*'
or **Run." In the *'Ofif'' position the ignition is
inoperative and the motor-dynamo is disconnected
from the battery. In the ** Start," or **Run,'' posi-
tion, the ignition is turned on and the battery current
is allowed to flow to the motor-dynamo, making it act
as a starting motor. If the switch is left in this posi-
tion the motor-dynamo will act as a dynamo wheii
the engine speed is sufficiently high. In the ''Neu-
tral," or ''Idle," position, the ignition is turned on,
but the motor-dynamo is disconnected from the bat-
tery, so that no starting motor action will take place.
Some switches have a "Neutral" position in which
starting motor action can take place, but arranged in
such a way that the field circuit for the dynamo is
open and the unit cannot charge the battery. This
last arrangement is designed to prevent excessive bat-
tery charge on long runs, such as in touring.
Combined starting, lighting and ignition Switches
are also made in various forms. They may be simply
a collection of the separate switch units in one case, or
thex niay be designed to produce starting, lighting
or ignition by movement of one lever or button in
different directions. Such switches are marked on
the face-plate so that the operator need only follow
the directions to secure the desired result.
FUSES
A fuse consists principally of a short length of
wire of such a composition that it will carry a certain
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114 STARTING AND LIGHTING
amperage with very little resistance, but when this
amperage is exceeded will rapidly rise in temperature
to such a point that it will melt and thus break its
connection in the circuit and prevent further flow of
current. Fuses are used in either the lig£.ting or
charging circuit and oftentimes in both. The wire
may or may not be enclosed inside of a small tube.
When unenclosed they are called open-fuse links, or
simply fuse wire. This form is not safe to use around
a car because of the danger of fire from the exposed
flash should the fuse bum out. Enclosed fuses are
called cartridge fuses and may be surrounded witji a
tube of fibre or one of glass (Figure 50). With glass-
s.
Figure 50. — Glass and Flbre-Bodled Cartridge Fuses.
enclosed fuses it is very easy to discover when one
has been burned out by looking through the glass.
With fibre covering, burning of the fuse causes a
small blackened spot to appear at some point along
the tube, usually at the center. Fuses may always be
tested by attempting to pass current through them
and at the same time through a lamp or meter of some
kind. Failure to secure a flow indicates a blown
fuse, and it will be necessary to replace that one with
a new one. Their cost is so low that there is no
economy in attempting to renew the fusible wire.
Fuses are always rated according to the amperage
they will carry without burning out. The voltage
need not be considered in their selection. The proper
size to use will, of course, vary with the voltage and
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LAMPS AND WIRING 115
candlepower of the lamps supplied or with the flow
required through the charging circuit, field circuit or
other path of current in which they are placed. In
the absence jof definite instructions the following sizes
may be used. These are calculated f pr a six-volt sys-
tem. Higher voltages will require a smaller amperage
and fuses of lower rating.
Head lamps 15-ampere
Side lamps only 5- to 8-ampere
Tail and dash lamps 5-ampere
All lamps 20-ampere
Horn 15-ampere
Dynamo field fuses 3- to 10-ampere
Charging circuit fuses 20- to 45-ampere
A fuse should never be replaced with one of a
larger size than that specified by the car or equip-
ment manufacturer, and should never be replaced
with wire or nails. Fuses are only used at points
through which an excessive flow of current may occur,
and which will cause more or less serious damage
when it does occur. Replacement with such substi-
tutes in the lamp lines may result in burning out aU
the bulbs affected; in the dynamo field circuits the
result will be burned-out dynamo field windings, and
in the charging circuits the result will probably be
a ruined battery.
Cartridge fuses are held in spring clips at each
end. These clips should be set so that they hold the
fuse without looseness, and the contact surfaces be-
tween fuse and clip must be clean and bright. A par-
ticle of dust at this point will prevent any flow of
current. Trouble may be experienced with the fasten-
ings between fuse clips and their bases or between
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116
STARTING AND LIGHTING
the clip and the wire end to which it is attached.
These points should be examined in case of an open
circuit or a greatly diminished flow through a circuit
in which fuses are used. In case the end^s of a cart-
ridge fuse or the surfaces of the fuse clips are foipid
^ dirty or corroded they
^B should be cleaned and
brightened with sandpaper!
CIRCUIT BREAKERS
The disadvantage in the
use of fuses for protection
is that spare ones of the
right size must be at hand
for purposes of replace-
ment. Unless the right
fuse can be easily obtained,
it is a great temptation to
replace it with a length of
wire. To obviate this dif-
ficulty a magnetic circuit
breaker is often used which
rapidly opens and closes
the circuit because of ex-
cessive amperage. (See
Figure 51.) These circuit
breakers consist of an elec-
tromagnet around which passes the current flowing
in the circuit. Carried at a point near enough- the
magnet core to be influenced by it is a small arma-
ture, and to this armature is attached, either directly
or by springs, one contact through which the current
flows- on its way around the magnet and through the
circuit. A stationary contact is mounted so that
Figure
Lighting System
(Be- ^
Circirit Breaker (Delco)
A — Mfignet Armature.
B — End of Magnet Core.
C — Arm Attached to Armature,
D — Bumper on Movable Contact
Arm.
E — Circuit Opening Contacts.
F— Spring.
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liAMPS AND WIRING IIT
it touches the movable one, and as long as they re-
main together the current flow can continue.
Should the amperage x>assing around the magnet
become too great for safety, the armature is attracted
and the contacts are separated, because the magnetism
produced will overcome the strength of the spring
that normally holds the contacts together. The circuit
breaker contacts may then remain apart or come
together again, depending on the design. With no
other parts than those described, the contacts will
immediately come together after they once open, be-
cause the flow around the magnet is stopped when they
separate. With no flow around the magnet the spring
will again cause the circuit to close, and the action
will be repeated rapidly, with a continuous clicking
or buzzing noise, until the cause of the excessive flow
is eliminated.
Other forms of circuit breakers are so constructed
that the movable arm is caught and held by a latch
so that the circuit is not again closed after once being
opened. A handle or trigger is arranged so that the
driver may release the latch and allow the breaker to
return to its operative position. The adjustment of
a circuit breaker spring should never be changed,
because this would have the same effect as if fuses
were replaced with others of higher capacity. The
tension is just right for the current to be carried,
and any increase will probably result in damage.
LAMP DIMMING
It is often desirable to reduce the amount of light
or candlepower of the head lamps to prevent glare
being thrown in the eyes of drivers of approaching
cars. This dimming is required by law in many parts
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118 STARTING AND LIGHTING
of the country, and must be provided for in some
way or other on all cars. The method that has been
used for the longest time is that of providing addi-
tional lamp bulbs of smaller candlepower than those
used for the large head lamps. These small bulbs
are often called ** dimmer" bulbs or ** pilot" bulbs,
and may be carried inside of the head lamp housing
or in a small extension from some point on the lamp
housing. Additional circuits are then arranged so
that these small bulbs may be lighted when the lai^e
Figure 52. — Dimmer, Marker or Pilot Bulb in Headlamp (Left).
Connections for Series System of Lamp Dimming (Bight).
ones are turned off, and the light is thus cut down to
the proper point.
Two other methods are in use, both of which cut
down the flow of current through the large head-lamp
bulbs to such an extent that the candlepower is much
reduced. One method acts to place the two head-
lamp bulbs in series with each other across the ter-
minals of the battery (Figure 52). The resistance
of the two lamps in series is twice as great as that
of either one of them alone, and the flow of current
through them is therefore reduced to half of its
former value. Inasmuch as this means a reduction
of the watts consumed in each lamp, the candlepower,
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LAMPS AND WIRING 119
which depends on the watts, is reduced in proportion.
Switches are arranged on the dash, or at any con-
venient point, so that the driver may place the lamps
in -parallel fo^ bright lighting or in series for dim-
ming. With the parallel connection each lamp bulb
is connected directly to the two battery terminals so
that each bulb receives the full battery voltage and
takes its normal amperage. The arrangement is
usually called series-parallel dimming.
Another method commonly used does not require
the additional wiring called for by the series-parallel
connection, and is, therefore, more easily applied.
Figrure 53. — Switch Connections for Resistance System of Lamp
Dimming.
This method consists of a length of wire of high
resistance that may be placed in the lamp circuit or
withdrawn from the circuit, according to the driver's
use of the switches. (See Figure 53.) The added
resistance of this wire prevents the full amperage
from reaching the lamp bulbs, and they bum less
brilliantly. The extent of the dimming may be con-
trolled by changing the length of resistance wire
placed in the circuit, and with this form in use the
lights may be made brighter by connecting two Or
more coils of the dimming resistance together with
copper wire so that the lamp current will flow through
the copper wire in place of passing through the resis-
tance in the short-circuited coils.
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CHAPTER V
CONTEOLLING DEVICES
CUT-OUTS.
All electrical equipments that include a dynamo
for charging the battery must have a switch of some
kind for disconnecting these two units from each
other while the engine is idle or running at speeds so
low that the voltage generated is not sufficient to
cause chai^ng to take place. But three principal
types ai*e in use, one being operated automatically by
an electromagnet, another by a centrifugal weight,
and the third being operated manually by the driver
of the car. The switch of the third type is so con-
nected that it will be operated with the starting
switch or with the ignition switch, and thus the danger
of leaving the charging circuit closed is avoided.
Electromagnetic Types. — The type of cut-out in
most general use makes use of an electromagnet whose
windings are connected between the dynamo brushes
at all times. This magnet consists of a core of soft
iron around which is wound a coil of many turns of
fine wire. One end of this coil is connected electrically
to one side of the dynamo and the other end of the
fine wire coil is connected electrically to the other side
of the dynamo. The magnet winding is, therefore,
in shunt with the charging lines from the dynamo,
and is called the shunt winding of the cut-out. The
120
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COKTROLLING DEVICES
121
proper operation of the cut-out depends on the action
of a second coil of wire being added to the shunt coil.
This second coil is so connected between the dynamo
and the battery that all of the current passing through
one side of the circuit from the dynamo during the
time the cut-out contacts are closed will flow around
this second coil. This winding is called the series
coil of the cut-out/ and the necessity for its presence
will be considered after the action of the shunt wind-
ing is explained.
^-a.
Figure 64. — Principle of the Afagnetic Cut-Out.
Figure 54 illustrates the principle upon which the
Cut-out switch is closed. The winding of the magnet
M is connected to the dynamo brushes as shown. The
wire of which this winding is composed is so small and
there is such a great length of it that th6 resistance
through the coil is great enough to prevent more than
a very slight flow of current passing through it. This
avoids too great a loss of dynamo current through the
cut-out itself. Mounted at some point on a hinged or
spring arm above the core of the magnet is the magnet
armature A, and when the magnetism in the cut-out
magnet is great enough in strength, this armature will
be attracted to the end of the magnet, overcoming the
strength of the spring 8. This will close the contacts
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122
STARTING AND LIGHTING
C, and a circuit completed through the wires X and
Y will be closed by the movement of the cut-out
armature.
With the dynamo idle there will be no pressure or
voltage between its brushes and consequently no cur-
rent will flow through the magnet winding. As soon
as the dynamo starts to revolve some voltage will be
generated, and this voltage will cause a flow of cur-
rent through the cut-out shunt winding. The tension
of the cut-out spring 8 is set at a point that holds the
Pignpe 66. — lElementary Magnetic Cut-Out with Battery Connections.
armature A away from the magnet, and consequently
holds the contacts C apart until the dynamo voltage
has risen above the voltage of the battery to which
the dynamo is attached. When the dynamo is oper-
ating at a speed high enough to cause a voltage in
excess of that of the battery the contacts C will be
brought together, and the circuit through wires X
and Y will be completed.
In Figure 55 the dynamo is shown connected to the
battery. The wire has been connected from one
dynamo brush to the wire X and the wire P has been
connected from the wire Y to one terminal of the
battery. The other dynamo brush is connected to the
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CONTROLLING DEVICES 123
remaining terminal of the battery through the wire R.
Closing the contacts C will now connect the dynamo
and battery, and inasmuch as the voltage of the
dynamo is above that of the battery before the con-
tacts close, the battery will be charged by current
from the dynamo.
The connections and arrangement shown in Figure
55 would be satisfactory for closing the circuit be-
tween battery and dynamo, but would not open it
properly in practice. Theoretically, the spring S
would pull the contacts apart when the dynamo volt-
age falls to a point below that necessary to hold the
contacts together. In actual operation the following
action takes place : At the instant when the dynamo
voltage becomes just equal to that of the battery as
the dynamo speed falls, there will be no flow through
the cut-out shunt coil. If this condition lasted for
any appreciable time the contacts would open, but
the falling dynamo speed immediately allows the
voltage to become less than that of the battery, and
before the contacts can open a flow of current starts
from the battery to the dynamo through the closed
contacts C and the wires P, Y, X, and B, because
the battery voltage is above that of the dynamo. A
part of this flow will pass through the wires 8 and T
and through the cut-out winding, thus holding the
contacts together and allowing the battery to dis-
charge through the dynamo. The cut-out remains
closed at the comparatively low voltage of the battery
because of the fact that it does not take as much
magnet strength to hold the armature down as
to draw it down across the air gap in the flrst
place.
To overcome the fault just outlined, the connec-
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124
STARTING AND LIGHTING
tions shown in Fi^re 56 are used, this being the
method actually used. The wire S has been combined
with the wire because both of them ran from the
left-hand brush to the cut-out. The connection is
completed from the end of through the shunt coil
of the cut-out just as it was completed from the end
of /S in Figure 55. The wires T and R have been
combined into the wire B up to the cut-out and the
current that has passed through the shunt coil of the
cut-out returns to the dynamo through wire R. The
r-37 1
Figure 56. — Complete CMnnections for Electromagnetic Cut-Out.
shunt coil therefore closes the contacts just as it did
before.
The current from the dynamo that passes to the
battery through the closed contacts now enters the
cut-out at the terminal marked D, and flows around
the additional coil S on the cut-out magnet, then to
the contacts and from the terminal B through the
wire P to the battery. The flow through the two coils
on the magnet is in the same direction and the
strength of the magnet is increased after the contacts
close. This effect is, however, incidental. The cur-
rent that has passed through the battery then returns
to the dynamo through the wire B, passing by the
cut-out terminal DB and flowing through B with the
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CONTROLLING DEVICES 125
current that has passed through the shunt winding
of the cut-out.
Now consider what happens when the dynamo volt-
age falls below that of the battery, ^ow from the
battery will take place just as soon as the dynamo
voltage is low enough, but this flow must pass around
the cut-out coil iS in a direction opposite to its direc-
tion during charge. Part of this current will also
pass through the lower shunt coil just as it did
before, but the two coils now oppose each other be-
cause the flow of current is in different directions
through them and the strength of the magnet will be
completely destroyed as soon as the battery dischai^e
through the coil 8 becomes great enough to overcome
the strength of the coil M. At this time the contacts
will be opened by the action of the spring and fur-
ther discharge from the battery will be prevented.
For the reason outlined, there should always be a
slight discharge from the battery just before a cut-
out of this type opens*
The second coil marked 8 and placed in series be-
tween dynamo and battery has another effect that is
of importance. It will be realized that a cut-out
having only the shunt coil would close and open at
the same dynamo voltage. That is, if it closed against;
the spring tension at seven volts, it would reopen
tinder the effect of the spring at seven volts. Should
the car be driven at such a speed that exactly seven
volts, or any other voltage corresponding to the spring
tension, were to be generated, the cut-out would open
and close continuously with damage to the contacts
from the excessive hammering and sparking. With
the series coil in use this action is prevefated for the
following reason : The cut-out closes under the action
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12(5 STARTING AND LIGHTING
of the shunt coil acting alone, because the series coil
carries no current until the contacts close. This will
make the closing point come exactly when the strength
of the shunt poil alone is sufficient to overcome the
spring tension. After the contacts are closed the
series coil adds its strength to that of the shunt and
the strength of the magnet is iacreased.v If now the
dynamo voltage falls to the point at which the cut-out
closed, it will noit reopen because the Inagnet is
stronger than when closing took place. The contacts
will therefore stay closed until the combined strength
of both coils is as low as the strength of the shunt
coil alone when closing took place. .In practice the
cut-out should stay closed until the speed of the car is
about two miles per hour below the speed of closing,
that is, the speed at which the contacts wiU reopen
will be about two miles per hour less than the speed at
which they close. This prevents rapid opening and
closing at some critical speed of the dynamo and car.
As stated, the connections shown in Figure 56 are
those generally used. Separately mounted cut-outs of
this type usually have three terminals; one, D, leading
to the dynamo only; another one, B, leading to the
battery only; and the third one, DB, being attached
to both dynamo and battery.
The most common practice places both windings on
one core as shown and explained. In some cases, how-
ever, two separate magnets are used, one carrying the
series coil and the other carrying the shunt winding.
Other types use two cores with part of each coil on
each of the cores. These two cores, with either ar-
rangement of windings, may be placed side by side or
one above the other. With some systems the arm that
carries the movable cut-out contact also carries one or
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CONTROLLING DEVICES
127
two of the magnets. Such a method is used with
Adlake equipment, there being two sets of magnets,
one set stationary and the other movable. The mova-
ble* set carries one contact and is attracted to the sta-
Figure 57.— *Cut-Out to Break Both Sides of Circuit (Leece-
Nevllle).
1 — Battery Leads.
2 — Movable Contacts.
3 — Bumpers on Magnet Arma-
• ture.
4 — Magnet Armature.
5 — stationary Contacts.
6 — Series Magnet Winding.
7 — Sliunt Magnet Winding,
8 — Magnet Pole Pieces.
9 — Terminals for Dynamo
Ijeads.
10 — Terminals for Battery
Leads.
12 — Springs for Plungers.
13 — Dynamo.
14 — Battery.
tionary set which is on top. The weight of the lower
movable set is depended on to open the contacts and no
spring is used.
Cut-outs are sometimes made with two sets of con-
tacts, one set being on the positive side of the charging
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128 STARTING AND LIGHTING
circuit and the other set on the negative side. This
, type of cut-out will have four terminals, as shown in
Figure 57. Four terminal instruments have been
used with Leece-Neville and with Wagner systems.
It will be realized that a small* flow of current
is passing through the cut-out when the contacts open,
this being the current that is passing from the bat-
tery through the series coil and dynamo and also that
passing through the shunt coil. Breaking any circuit
through which current is flowing will cause a spark
and this spark is intensified when, as in this case, a
Figure 58. — Double Contacts for Cut-out. A — High Resistance
Contacts to Take Spark. B — Low Resistance Contacts for Charging
Current.
coil of wire is included in the circuit. To prevent this
sparking from causing damage to the contacts the
construction shown in Figure 58 is often used. The
two contacts are shown at A and B. Contacts A are
made from carbon or any other material that is a
fairly good electrical conductor and that is not easily
affected by sparking. The upper or movable contact
of the pair marked A is carried on a small flexible
extension of the main cut-out arm and the contacts of
this pair are closer together than the pair marked B.
Both of the upper contacts move at the same time
when the cut-out armature is attracted to the magnet,
but the pair marked A will close before those marked
B and when the armature is released by the magnet
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CONTROLLING DEVICES 129
they will open before those marked B open. Contacts
B are those depended on to carry the bulk of the cur-
rent and they are made from metal of low resistance
which would be damaged by excessive sparking.
The action is as follows : The contacts A close first,
but as the armature is attracted further, contacts B
will also close because the flexible arm carrying the
upper contact A will bend slightly. With both pairs
of contacts together the current flows through both of
them, but most of it passes through the contacts B.
When the cut-out opens, the contacts B separate first,
but as current can still fiow through contacts A, no
spark is produced at B because the circuit has not
been completely broken. As the armature moves
away from the magnet to the full distance, the con-
tacts A also open and the spark takes place between
them. Because of their higher resistance the current
flow has already been reduced to such a point that the
spark that does take place is not so severe as if the
circuit had been broken at its full strength.
Cut'Out Adjustment. — The time, or dynamo speed,
at which an electromagnetic cut-out will operate de-
pends on two adjustments. One of these is the ten-
sion of the spring when a spring is used, and the
other is the distance between the magnet core and the
armature of the magnet. With increased spring ten-
sion the voltage, and consequently the dynamo speed,
required will be increased. With an increased air
gap between the magnet core and its armature the
voltage and dynamo speed necessary to close the con-
tacts will also be increased. Making the spring ten-
sion less or decreasing the air gap will lower the
dynamo and car speed at which the cut-out closes.
Increasing the spring tension or widening the air gap
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130 STARTING AND LIGHTING
will raise the dynamo and car speed of cut-out closing.
Some systems provide for one method of adjust-
ment, some for the other and some for both.
In some cases no special provision has been made
for either method of adjustment, but one or the
other of these conditions can always be changed. In
making cut-out adjustments the following points
should be considered. With the cut-out open the mag-
netism must act across the air gap and consequently
this gap affects the speed and voltage of cut-out
closing. With the contacts once closed there is little
or no air gap between the magnet core and its arma-
ture, and therefore the length of the gap has no
effect on the time at which the cut-out will reopen.
On the other hand, the spring tension is not much
changed whether the cut-out be open or closed, and
therefore the spring tension will affect the opening
and closing about equally.
The cut-out should close just as soon as the dynamo
voltage is above that of the battery. With a six-volt
battery, the cut-out should close when the dynamo
voltage is between 7 and 7^2- With batteries of more
cells and higher voltage, the dynamo voltage of doss-
ing should be in proportion. The cut-out should open
when the discharge current flowing through the series
coil and from the battery is between zero and two
amperes. Improper operation may take place in any
of the following ways:
1. Closing at a voltage below that of the battery.
This will allow a discharge to take place until the
dynamo runs fast enough to raise the voltage. Either
the spring tension may be increased or the air gap
increased.
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CONTROLLING DEVICES 131
2. Closing at a voltage much higher than that of the
battery. This will prevent charging at speeds as low
as might be used, and the time during which the car is
operating below the cut-in speed is lost as far as bat-
tery charging is concerned. The remedy is to lessen
the air gap or decrease the spring tension.
3. Closing at too high voltage and remaining closed
until an excessive discharge takes place. This will
lessen the total time during which the battery charges
and will increase the time of discharging. Lessen the
air gap and increase the spring tension.
4. Closing at too high a voltage and opening before
a discharge takes place. Decrease the spring tension.
5. Closing with the dynamo voltage equal to or
below that of the battery and remaining closed until
an excessive discharge takes place. Allows the bat-
tery to discharge. Increase the spring tension.
6. Closing at too low voltage and opening before a
discharge takes place. Decrease the spring tension
and increase the air gap.
The current carrying contacts of the cut-out must
be kept clean and bright and must meet with their
whole surfaces in contact. Should the contacts be
found dirty or pitted they may be properly fitted by
passing a narrow strip of very fine emery cloth be-
tween them, then pressing them together and drawing
the cloth back and forth. After one contact is cleaned
the cloth should be turned over and the surface of the
other contact treated in the same way. It should be
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132 STARTING AND LIGHTING
noted that some contacts are made with a ribbed sur-
face and such forms should not be dressed with emery-
cloth, as this would destroy the ribs. This method of
cleaning may be applied to contacts of metal or of
carbon. Carbon contacts can be handled very satis-
factorily with fine sandpaper or cloth in place of
emery cloth.
The contacts of an electromagnetic cut-out should
not be pressed together unless one of the wires from-
either battery or dynamo can be quickly removed.
With the contacts together the flow of battery current
around the series coil and through the shunt winding
may hold them closed with a resulting discharge from
the battery. All cut-outs are not subject to this ac-
tion, those in which the armature never comes very
close to the magnet core generally being free from it.
Removing the wire that leads to the dynamo or the one
that leads to the battery will stop the flow of current
and will allow the contacts to open. Starting the
engine will stop the flow from the battery and send it
in the other direction. When the engine is allowed
to stop, the contacts will open.
Various locations are used for electromagnetic cut-
outs, these varying with the design and make of the
equipment. In some cases this part of the apparatus
will be found inside of the dynamo housing, either in
the brush and commutator compartment, in a housing
adjacent to the brushes and commutator or under-
neath the arch of inverted U magnets. The cut-out
will oftentimes be carried on the outside of the dy-
namo case. Either of these methods allow of the
minimum length of wiring between dynamo and cut-
out and make it necessary to run only two wires away
from the dynamo with a two-wire system or one wire
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CONTROLLING DEVICES
133
with a one-wire system. Other locations for the cut-
out are on the dash, under the front seat, under the
floor boards, on the cowl board, with the regulating
device or with the starting, lighting or ignition switch,
Hand-Operaied or Manual Cut-outs. — A number of
systems are built in which the electromagnetic cut-out
is dispensed with and in its place is used some form
of switch that breaks the connection between the
djTiamo and battery when the engine is not running.
This type of cut-out switch is attached to the same
Figure 59. — Manual Cut-Out and Starting Switch (Dyneto-Entz
Type).
handle, button or lever that operates either the start-
ing switch or the ignition switch. When attached to
the starting switch the ignition is also operated by
the starting switch handle so that it might be said
that a manually operated cut-out will always be inter-
connected with the ignition switch in such a way that
the circuit will be closed between dynamo and battery
when the ignition is turned on and will be broken
when the ignition is stopped.
The action of one form is shown in Figure 59. This
♦type of switch has been extensively used with Dyneto
and with Entz equipment, and one similar in princir"
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134 STARTING AND LIGHTING
has been used with Westinghouse and Bijur systems,
always in connection with a combined motor-dynamo
having one armature and operating as a starting
motor at low speeds while changing to a dynamo at
higher speeds. The switch is composed of a blade and
handle B, pivoted at 0. The position with the engine
idle is shown in full lines, while the starting and run-
ning position is shown in dotted lines. The form
illustrated is designed for use with a high tension
magneto and in the off position the line from the mag-
neto armature is grounded through the contacts 4 and
5 which are connected by the short extension of the
switch blade on one side of the pivot.
With the switch moved to the running and starting
position, the magneto ground is removed and the
ignition will become operative. At the same time the
current flows from the right hand brush of the dy-
namo through the series field (reversed for regulating
purposes during action as a dynamo) and to the bat-
tery. From the left-hand brush current flows to
switch contact i, through the blade to the contacts 2
and 3, From contact 2 the charging current passes
to the battery and from contact 3 a part of the current
passes to the shunt field of the dynamo. Midway
between the ''Oflf'' position and the ** Start'' or
**Run" position, is a point called **Idle" or ** Neu-
tral." With the switch in this position, the ignition
ground will be removed and the ignition operative,
the contacts 1 and 2 will be connected so that the bat-
tery is connected to the starting motor, but contact 3
is disconnected so that the dynamo is prevented from
generating because the shunt field circuit is not com-
plete. This position would be used for touring or
when the battery has been sufficiently charged.
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CONTROLLING DEVICES
136
A variation of this switch is shown in Figure 60 in
which the leads to the contacts have been changed.
The ignition and starting connections are the same in
effect, but with the switch in the position half way
between *'Off" and ''Start'' the battery is discon-
nected and the shunt field is open so that no flow can
take place from battery to motor-dynamo at low
engine, speeds and neither can current be generated by
the machine as a dynamo. This has the effect of pre-
Figure 60.-
-Manual Cut-Out and Starting Switch (Dyneto-Enta
Type).
venting useless battery discharge when the car is
being operated at speeds so low that the dynamo volt-
age would not be high enough to charge the battery.
It also prevents the generation of current while the
battery is disconnected because of the opening of the
shunt field circuit. Except for this switch, current
generated with the battery disconnected would have
to flow through the field windings and would be so
much greater than these windings are designed to
carry that the coils would be burned out. This con-
nection, shown in Figure 60, is the one most used.
Similar arrangements are secured by the use of
switches of rotary form rather than the knife type
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136
STARTING AND LIGHTING
shown. The principle and the conneetion& made
remain the same, regardless of the style of switch used.
A type of cut-out switch that is operated with the
ignition switch and that has been used with a great
many Delco equipments is shown in Mgure 61. When
the switch button is pulled out, the contacts A and B
are both closed at the same time. Current for ignition
then flows from the battery through the wire to switch
terminal 1 and through the wire X and the circuit
breaker (not shown) to the ignition contacts A. From
Figure 61. — ^Manual Cut-Out Switch (Delco).
these contacts the flow continues through switch ter-
minal 8 to the ignition cail and then through tiie
ignition breaker to ground, from where it returns to
the battery.
With the ignition turned on as described, the engine
can be started. The dynamo will quickly generate a
voltage high enough to cause battery charging, and
the flow will take place from the dynamo commutator
to switch terminal 7, then through the contacts B and
through the terminal 1 to the battery. Part of this
dynamo current will then pass through the ignition
contacts of the switch and will take the place, of the
battery current supplied while starting the engine.
One side of the battery and one side of the dynamo
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CONTROLLING DEVICES 137
are grounded so that the charging circuit is com-
pleted. A discharge of current will take place from
the battery through the switch terminals 1 and 7 and
through the contacts B during the time that the
switch is closed and before the engine starts. This
reverse flow or discharge will also take place when
the engine runs at a speed so low that a charging
voltage is not maintained. The proportion of dis-
charge to charge is so very small that its effect on
the battery is negligible. When the engine is to bo
stopped the switch is opened by pressing in on the
button and both the ignition and charging circuits are
broken. The dynamo is then disconnected from the
battery while the engine remains idle.
It is of course impossible to make any adjustments
on hand-operated cut-out switches because of the fact
that their operation depends on the time at which
either the starting switch or the ignition switch is
used.
DYNAMO OUTPUT CONTROL
The details of the methods in use for limiting and
regulating the battery charge rate in amperes are
many. While the applications of the several prin-
ciples differ more or less from each other in almost
every make and every type of equipment, they may
be divided into several distinct classes, according to
the ways in which they secure the desired result.
Constant Voltage or Control of Current, — All
methods of regulation may be classified under two
heads. One class causes the dynamo voltage to re-
main at a constant and unvarying point after the cut-
out closes, while the other class makes use of princi-
ples that allow the voltage of the dynamo to change so
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138 STARTING AND LIGHTING
that the desired flow in amperes is given to the battery
through control of the voltage, but not through keep-
ing it at a constant value. While both methods are
in common use, the latter has been used in greater
numbers than has the first one.
The rate of flow in amperes from the dynamo to
the battery always depends on the difference in volt-
age between these two units. Should a battery with
a pressure of six volts be attached to a dynamo that
was generating exactly six volts, there could be no
flow, because the twb pressures would balance each
other. The condition would be similar to that which
would exist with a water tank attached to a water
pump when the pressure in the tank was six pounds
and the pressure from the pump was also six pounds.
It is evident that there could be no flow in either case.
It will be remembered from the explanation of volts,
amperes and ohms in Chapter I that the amperage
flowing through a circuit may be found by dividing the
voltage by the resistance of the circuit. The resist-
ance of the wiring and connections between dynamo
and battery, plus the resistance of the battery itself,
make up the total resistance of the charging circuit,
and the voltage acting will always be the difference
between that of the dynamo and of the battery. For
purposes of explanation, it may be assumed that the
resistance through the charging circuit will remain
unchanged at all times, and in the following explana-
tion on this subject, this condition has been taken for
granted.
It will then be evident that any increase of dynamo
voltage above that of the battery will result in an
increased flow and the change of flow will be in pro-
portion to the change in difference of voltage between
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CONTROLLING DEVICES 139
\ dynamo and battery. Two things will always act to
increase the dynamo voltage with a straight shunt
wound machine, these being increase of armature
speed and increase of current flowing around the field
coils. With a shunt wound dynamo these will in-
crease together for the reason that increased voltage
at the brushes caused by increased speed will result
in an increased flow through the field windings because
of this higher voltage. The total result will be a still
further increase in generated voltage, also a corre-
sponding increase of amperage through the circuit.
The dynamo armature is generally driven positively
from the engine at all speeds so that its speed in-
creases directly in proportion to increase of car and
engine speed. The dynamo voltage would therefoi^'e
naturally rise continuously from the lowest to the
highest speeds. In some cases the speed is limited by
a governor that releases the driving connection when
the desired number of revolutions per minute has
been reached and the dynamo cannot generate a volt-
age in excess of that caused by this maximum speed.
With the generally used type of dynamo operating
at a variable speed the method of output control will
act to decrease the field strength with increase of
speed so that the weakened field counteracts the more
rapid rotation of the armature to a greater or less
extent and the dynamo voltage is held within certain
desired limits. Another method makes use of the
change in direction of the lines of force through the
armature. Depending on the piethod used, any of
the following effects may be secured:
1. An increase of voltage throughout the whole
range of dynamo speed, the voltage, however, increas-
ing less rapidly at high speeds than at low.
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140
STARTING AND LIGHTING
2. A gradual increase of voltage until a maximum
is reached at some critical speed, followed by a falling
off in voltage as the speed becomes still greater.
Figure 62. — Output of Dynamo Having Gradual and Continuous
Increase (Reversed Series).
Figure 63. — Output of Dynamo Having Quick Rise to Maximum,
Followed by Decrease (Third-Brush).
3. A comparatively sudden rise in voltage through
the low speed ranges until a critical point is reached,
after which the voltage is maintained at a point just
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CONTROLLING DEVICES
141
sufficient to cause a constant amperage to flow from
dynamo to battery. •
The characteristics of the three types are shown in
Figures 62 to 64. The rate of speed corresponds to
the series of vertical lines, and increases from left
to right. The voltage and consequent amperage flow-
ing are indicated by succession of horizontal lines,
and the increase is from bottom to top. Figure 62
represents the condition numbered **1" in the fore-
Figure 64. — Output of Dynamo Having Constant Amperage
Regulation.
going explanation. Figure 63 represents the condi-
tion outlined in number **2," while Figure 64
shows the result obtained in number **3.'' These
types include the methods that are classed as amperage
control, or limited output control, but do not repre-
sent the second general classification known as con-
stant voltage or ** constant potential.''
Constant Voltage. — It was explained in Chapter III
that the voltage of the battery increased as the charge
progressed and that the voltage of a fully charged bat-
tery is higher than the voltage of a battery that is
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142
STARTING AND LIGHTING
discharged or partially discharged. If a dynamo is
operated in such a way that the voltage generated will
remain constant at one value over practically the
whole range of armature speed it will be seen that the
difference in voltage between the dynamo and battery
will depend not only on the dynamo but also on the
voltage of the battery at any particular time. With
a nearly discharged battery of low voltage, the dif-
ference between dynamo and battery will be compara-
Figure65. — Output of Dynamo Havinsr Constant Voltage Regulation.
tively great, while with a battery that is nearly
charged and of correspondingly high voltage, the dif-
ference will not be so great. For this reason the flow
from the dynamo to a discharged or partly charged
battery will be caused by a comparatively large dif-
ference of voltage, and this flow will be relatively
great in amperage. The flow from the constant volt-
age dynamo to a battery that is nearly or fully
charged and of correspondingly high voltage will be
caused by a smaller difference in pressure, and the
amperage will therefore be relatively small. This
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CONTROLLING DEVICES 143
action gives what is known as a 'Capering charge,"
that is, a charge whose amperage becomes less and
less as the battery becomes charged and as the battery-
voltage increases. The characteristics of such regula-
tion are shown in Figure 65, in which the percentage
of battery charge from zero to full charge is shown
from left to right while the amperage or voltage dif-
ference is shown by the horizontal lines and decreases
from top to bottom. In this connection it should be
borne in mind that the specific gravity of the battery
electrolyte increases with increase of battery voltage,
and it may therefore be stated that the rate of charge
in amperes will be greater at low specific gravities
than at high.
Output or Voltage Regulation, — ^Four principal
methods or devices are in use for securing control of
the dynamo voltage and output. They may be classi-
fied as follows :
I. Inherent characteristics of the dynamo design
that do not require the use of any additional moving
parts but that secure the desired results through the
peculiarities of electric currents, conductor and mag-
netism. This class includes compound and reversed-
series field windings, also a variation somewhat simr
41ar to the reversed series and known as a ** bucking
coil.'' A type of dynamo having one or more brushes
in addition to those for the charging lines is also in-
cluded in this class, this type being known as the
''third brush" machine. In this case the added
brushes carry the field current for the shunt winding.
II. Electromagnets that act to increase the resist-
ance of the shunt field circuit, or to open the shunt
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144 STARTING AND LIGHTING
field under certain conditions, or to make changes in
the field circuits.
III. Centrifugally operated governors that act to
prevent an armature speed above a predetermined
limit or that insert a resistance in the field circuit or
chaining circuits.
IV. Ampere-hour meters that change the field cir-
cuit resistance according to the number of ampere
hours that pass into or out of the battery.
The four classes just mentioned are found in a total
of sixteen different applications, each of the sixteen
being a distinct type of regulation and used by one or
more makers of electrical equipment. Each applica-
tion will be described, and when used by a limited
number of makers, their names will be given in con-
nection with the description. The applications under
each division are as follows:
I. Inherent Characteristics.
(1) Reversed-series field winding.
(2) Third brush for shunt field current.
(3) Compound field windings.
(4) Bucking coil (iron wire control).
II. (5) Magnetic vibrator inserting field resistance.
(6) Magnetic vibrator energizing bucking coil.
(7) Magnetic vibrator for field resistance, with
load control.
(8) Magnetic controlled carbon field resistance.
(9) Magnet acting to open field circuit.
(10) Solenoid operating rheostat field resistance.
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CONTROLLING DEVICES 145
(11) Magnet and mercury well control of field
resistance.
(12) Changing combinations of fields and wind-
ings.
III. (13) Speed control governor with compound field
winding.
(14) Speed control governor with permanent
field magnets.
(15) Governor inserting field resistance.
IV. (16) Ampere-hour meter control of field circuit.
The numbers that appear at the beginning of each
of the following descriptions refer to the numbers
given in the foregoing list of applications.
(1) The principle upon which the reversed-series
field winding system operates has been described in
Chapter II, and a lengthy description is therefore
unnecessary at this time. The application of this
method of regulation in one type of Auto-Lite dynamo
is shown in Figure 66. This machine carries two
windings on each of the field magnet poles, one wind-
ing being the usual shunt and the other one being a
series coil through which the current, passing from
dynamo to battery, flows in a direction the reverse
of that taken by the current passing through the shunt
coils. From the lower brush, which is positive, cur-
rent passes to both coils on the lower pole piece, part
passing through the shunt field in such a direction that
this pole end is made positive. This current is then
carried to the upper shunt field winding and passes
around this upper pole piece in such a direction that
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146
STARTING AND LIGHTING
its end is also made positive. The consequent poles
thus formed at either side of the armature are there-
fore negative.
The portion of the eurtrent from the positive brush
that is not required for the shunt field, passes around
Figure 66. — Dynamo Having Reversed Series Regulation (Auto-
Lite),
1 — Series Field' Windings.
2— Shunt Field Windings,
3 — Brushes.
4 — Connection for Shunt Windings.
5 — Dynamo Shaft.
6 — Commutator.
7 — Armature.
the lower pole piece in a direction that tends to oppose
the shunt winding and to make this pole end of less
strength. After passing around the magnet, the cur-
rent is led to the lower terminal and then to the bat-
tery. The current returning from the battery to the
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CONTROLLING DEVICES 147
upper dynamo terminal, comes into the upper series
winding and passes around the magnet in a direction
that tends to weaken this upper pole, thus opposing
the shunt winding. Having traveled around the wind-
ings, the current joins with that from the upper shunt
coil and is led to the negative brush. While this exact
method of winding is not always followed, the prin-
ciple is the same in all applications of this method,
that is, to cause the charging current passing around
the series windings to oppose the effect of the shunt
winding.
(2) Third brush regulation depends on two elec-
trical facts. One is the fact that the voltage* between
a brush of a two-pole dynamo and point on the commu-
tator away from this brush depends on the distance of
the point from the brush and becomes greater as the
distance increases. The greatest voltage difference
will therefore be secured between opposite points on
the commutator. If one end of the shunt field wind-
ing be connected to one brush and the other end of
the winding lead to a brush that is not directly oppo-
site the first one, the difference in voltage acting to
send current through the shunt field will not be as
great as if the field were connected between brushes
directly opposite. If, then, the field current is to be
increased, the second brush may be moved farther
away from the first one and this movement will allow
a greater difference in voltage to act on the field and a
correspondingly greater flow in amperage and field
strength will result. The field strength may be de-
creased by bringing the brushes to which the winding
is attached nearer together. The brush that carries
one end of the winding is generally made movable, and
the output of the dynamo may be increased or de-
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148
STARTING AND LIGHTING
creased by moving the brush away from or toward the
stationary brush. While such brushes may be made
movable for purposes of adjustment, they are locked
in one position while the dynamo is in operation, the
control of voltage being secured, not by continually
moving the brush, but as described in the following
paragraphs.
The connections for regulation in such a system are
shown in Figure 67, the type shown being used with
several models of Remy dynamos. The principle and
Figure 67. — Dynamo with Third Brush Regulation.
action will be the same, regardless of the make of
equipment or its model, so long as the third brush
system is used. Current for charging is taken from
the main brushes marked A and B, these being indi-
rectly connected to the battery. The shunt field <jur-
rent passes through the brush R and to the field coil,
then through the field fuse which is used to protect
the field winding against excessive current flow, and
from the fuse the field current returns to the brush B.
The difference in voltage between brushes B and B is
the voltage that acts to .send current through the field
coil. Were it possible to change the regulating brush
position, moving it down (toward brush B) would de-
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CONTROLLING DEVICES
149
crease the output of the dynamo, while moving it up
(farther from B) would increase the putput.
At low speeds the flow of magnetism^ or magnetic
lines of force between the poles of the field magnet is
shown in Figure 68. It will be seen that the flow is
practically straight across, and because of this direc-
tion of the lines of force through the armature, the
coils which are at any instant in connection with the
brushes, cut through the greatest possible number of
lines of force, and therefore the greatest difference in
voltage will be between the commutator points being
touched by the main brushes A and B. A less dif-
Figure 68. — Distortion of Field Magnetism for Third-Brush
Regulation.
ference in voltage will be maintained between the
points touched by the brushes B and B because of the
smaller number of lines of force being cut by the cor-
responding armature coils.
With increase of armature speed, the lines of force
do not continue to pass straight across, but are car-
ried part way around in the direction of rotation by
the core of the armature. With the magnetism flow-
ing in this distorted path, the armature coils that are
at any one time attached to the regulating brush
through the commutator, are not cutting as many lines
of force as at lower speeds, and the voltage difference
between the brush B and the brush B is less than with
the lines of force passing straight across. This reduc-
tion of voltage causes the amperage passing through
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150
STARTING AND LIGHTING
the shunt field to decrease, and even with the
rise in armature speed, the output does not increase
proportionately because of the weakened field. With
further increase of armature speed, the path of the
lines of force is still further distorted and the field
current drops to such an amperage that the total out-
put of the dynamo becomes less and less through the
highest speeds of rotation. The relation of dynamo
output to armature speed is shown by th^ curve in
Figure 63.
XI
<a
Figure 69. — Compound Wound Dynamo with Lamp Circuit Through
Series Field (Gray & Davis).
(3) The compound-wound dynamo is generally
used in combination with some of the other methods
of regulation. This machine makes use of a straight
shunt winding on the field magnets, and in addition
to this shunt winding, has a series coil through which
current flows in the same direction as through the
shunt and increases the field strength. Such an ar-
rangement is shown in Figure 69, this connection
being that used with some older types of Gray &
Davis dynamos that were equipped with a centrifugal
governor to limit the dynamo speed.
In this case it will be seen that current for the lamps
is carried through the series field winding, and when
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CONTROLLING DEVICES 151
the lamps are lighted, the strength of the series wind-
ing will be added to that of the shunt with a conse-
quent increase in dynamo output to care for the added
load placed upon the system by the lighting of the
lamps. With no lamps lighted, current from the
dynamo brushes flows to the terminals marked + and -
and from these terminals to the positive and negative
terminals of the battery. Should the lamps be turned
on, the current taken by the bulbs will not pass to the
battery, but from the + dynamo terminal through the
wire A to the lamps, then through the lighting switch
L and wire'B to the^ dynamo terminal S-. From this
terminal the lamp current passes around the series
coil, then to the dynamo terminal marked - and back
to the negative brush. Should enough lamps be
turned on to take more current than that being sup-
plied by the dynamo, the deficiency will be furnished
by the bq,ttery. This extra current will come from
the positive battery terminal to the lamps, then
through the bulbs and lamp switch to dynamo ter-
minal Sy through the series field so that it is still fur-
ther strengthened and back to the battery from the
dynamo terminal marked -.
(4) The system of regulation known as * ' iron wire ' '
control was introduced on the dynamos made by the
Rushmore Dynamo Works and is also used on some of
the products of the Bosch Magneto Company of which
the Rushmore Dynamo Works is a part. The dynamo
field magnets carry a shunt winding, and in addition
to the shunt, a second winding of fewer turns through
which current is forced to flow in a direction opposite
to that in the shunt coils by a peculiar property of
iron wire. A field coil, so wound that current passes
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152
STARTING AND LIGHTING
through it in a direction that opposes the shunt field
action, is called a ** bucking coil.'' In this case the
coil is not a series coil and does not carry the entire
dynamo output, therefore the system cannot be classed
as a reversed-series type.
Iron wire will carry a volume of current in propor-
tion to the gauge size, just as any other metal carries
current. Up to a certain amperage the wire will
remain comparatively cool, but as soon as this am-
perage is exceeded, the wire will become very hot and
^^
s
s '■
^
• ' 3
1 ,
^
- +
1
Figure 70.— ^Principle of Rushmore Iron Wire Regulation.
with increase of temperature, its resistance increases
to such a point that but very little flow of current can
take place through the wire.
The use of iron wire in the Rushmore system is
shown in Figure 70. Starting at the right-hand brush,
the charging current flows through wire 1 to the bat-
tery, through the battery and by wire 2 to one end of
the ballast coil C This ballast coil is made from a
certain gauge size of iron wire and always carries ten
feet of the size used. Passing through the ballast
coil and wire 3, the current returns to the negative
dynamo brush. Again starting at the right-hand
brush, the field current passes through wire 4 to the
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CONTBOLLINQ DEVICES 153
shunt field winding 8, through the coil and by way of
the wire 5 to the ballast coil, and through the iron
wire to wire 3 and the negative brush. It will thus
be seen that the bucking coil field winding B carries
practically no current under ordinary conditions.
When the amperage reaches a certain value, the iron
wire becomes very hot and further increase oi current
flow through it is prevented. This prevents increase
of flow through wires 5 and S, and the field current
that formerly passed through wire 5 must now take
the path through wire 6, through the bucking coil and
to the negative brush. This flow of current through
the bucking coil decreases the field strength and dy-
namo output. With decrease of output, the iron wire
cools and the current again takes its normal path
and leaves the bucking coil weak as before. By select-
ing a gauge size of iron wire that will keep just below
the critical temperature while carrying the desired
charging current, the output of the dynamo is pre-
vented from exceeding this amperage.
(5) A great many systems make use of a regulat-
ing device comprising an electromagnet whose strength
increases with increase of dynamo voltage and which
causes a high resistance to be temporarily inserted in
the shunt field circuit when the dynamo speed be-
comes high enough to cause excessive voltage and
therefore excessive amperage. The principle of such
a mechanism is shown in Figure 71. The three dy-
namo terminals are marked F, A and D; F being at-
tached to one end of the shunt field winding, A to one
of the dynamo brushes, and D to the other brush and
the remaining end of the field winding. The regulator
consists of the magnet M around which current from
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164
STARTING AND LIGHTING
dynamo terminal A flows through the wire 1 on its
way to the battery. It will be seen that this magnet
will become stronger as the amperage passing from
the dynamo to battery increases. The armature of
this magnet is held away from the core by the spring
B, and with the armature in this position, the con-
tacts C are closed.
Current for the shunt field leaves the dynamo at
terminal A, passing through the wire 1 to the contacts.
Figure 71. — Electromagnetic Regulator for Constant Amperage.
This current does not flow through the coil B because
this coil is made from wire with a very high resistance,
but the current takes the path of low resistance
through the contacts. From the upper contact the
field current passes to dynamo terminal F, through
the shunt field winding and to the left-hand brush.
As long as the amperage flowing to the battery around
the magnet M is not great enough to cause the magnet
to overcome the tension of the spring B, the above
conditions hold true. The spring tension is set at
such a point that when the desired maximum am-
perage of charging is reached, the magnet attracts
its armature and the contacts C open. The field cur-
rent can no longer pass through the contacts, but must
take the path through the resistance coil B. This
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CONTROLLING DBVICBS
155
resistance allows but a small current to pass through
the field, with a consequent reduction in field strength
and dynamo output. The decreased output results in
a lessened flow around the magnet M, and the contacts
are again closed by the tension of the spring B. In
practice this opening and closing of the contacts is
so rapid as to be almost imperceptible to the eye, and
the field current is maintained at such a strength that
the dynamo output cannot exceed the maximum for
which the spring tension is set, regardless of dynamo
Figure 72. — Electromagnetic Regulator for Constant Voltage.
speed. Increasing the spring tension or increasing
the air gap between magnet core and armature will
raise the amperage that the dynamo will give, while
decreasing the spring tension or lessening the air gap
will result in a lower amperage for charging. This
principle has been used in controllers made by Allis-
Chalmers, Delco, Disco, Gray & Davis, f^orth East,
Remy, .Simms-Huff, and Ward Leonard.
The variation of this method, shown in Figure 72,
illustrates the connections when it is desired to main-
tain a constant voltage at the dynamo rather than a
limited amperage, regardless of dynamo speed. The
sole difference is that the magnet M now has its coil
connected to the dynamo brushes through the ter-
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166 STARTING AND LIGHTING
minals A and 2>. Whatever voltage exists between
the dynamo brushes will therefore act on the magnet
winding. The strength of the magnet will increase
with dynamo voltage, and will decrease with drop of
dynamo voltage. The tension of the spring is set at
a point such that the armature will remain away from
the magnet core and the contacts will remain closed
until the dynamo voltage reaches the value that is de-
sired. At this voltage the magnet overcomes the
spring tension, the field current is forced to pass
through the resistance coil, and the lessened flow
through the fields causes an immediate drop in volt-
age. This drop in voltage weakens the magnet so
that the contacts are again closed by the spring, and
the operation is repeated at an extremely rapid rate.
The result is that the voltage of the dynamo will not
rise above the point that the spring is set for, regard-
less of the dynamo speed. The magnet winding in
this case is made from a great many turns of very fine
wire, so that but little current will flow through it.
The battery is connected between djmamo terminals
A and D so that current for charging does not pass
through the regulator. Increasing the spring tension
or increasing the air gap between magnet and arma-
ture will raise the operating voltage of the dynam.o,
while decreasing the spring tension or the air gap will
lower the dynamo voltage.
Systems using the vibrating forA of regulator prac-
tically always make use of an electromagnetic cut-out
with it. The two units are combined in one housing
and called a controller. The controller may use two
magnets, one for the regulator and one for the cut-out,
or may use but one magnet with two windings for
both functions. Such a combination is illustrated in
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CONTEOIiLING DEVICES
157
Figure 73. The single magnet is so arranged that it
will attract the right-hand armature for cut-out action
and the left-hand armature for regulator action. This
magnet carries a fine wire coil S which is the shunt
coil for the cut-out action, and also a coil of heavy
wire C which acts as the series cut-out coil and as the
main coil for the regulator in a way similar to that of
the type shown in Figure 71. The field resistance is
shown at R and the four terminals used with this type
of controller at F, A, DB and B on the controller case.
Figure 73. — Controller Connections with Magnetic Cut-Out and
Constant Amperage Begulation.
The action is as follows : When the dynamo is idle,
the cut-out contacts Y are open and the regulator con-
tacts X are closed. When the dynamo generates a
difference of voltage, current flows from dynamo ter-
minal A to controller terminal A, through the coil G
on the magnet, then through coil S to controller ter-
minal DB and to dynamo terminal D, The field cir-
cuit is completed from dynamo terminal A to con-
troller terminal A, through the closed contacts X and
from controller terminal F to the dynamo field ter-
minal, through the shunt field and to the left-hand
brush. The flow of current around the magnet causes
the cut-out contacts Y to close when the dynamo volt-
age is high enough to charge the battery, and the flow
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168 STARTING AND LIGHTING
from dynamo to battery passes through coil C to the
contacts Y which are now closed, then to controller
terminal B and to the battery. When the amperage
flowing through the coil C reaches the desired maxi-
mum, the left-hand armature is attracted to the mag-
net and the contacts X are drawn apart. The field
current then passes through the resistance R and the
regulating action is the same as that already described.
(6) A vibrating system that is seldom met with
makes use of a magnet similar to those just described.
When the contacts are drawn apart by excessive am-
perage through the charging circuit, the field current
is forced to pass around a series of bucking coils on
the field magnet poles. The bucking coils thus take
the place of the resistance used with the type described
under (5). Jesco systems have made use of a vibrat-
ing regulator that utilized a resistance coil and also
caused part of the field current to pass through buck-
ing field coils.
(7) The diagram of the circuits of the Gray &
Davis controller shown in Figure 74* illustrates the
use of a magnetic vibrator that is affected by the lamp
load in such a way that the output of the dynamo is
automatically increased whenever lamps are lighted
with the engine running. It will be seen that current
from the positive brush flows through a ground con-
nection for battery charging and that the current used
for exciting the fields fiows from the positive brush
through the upper and lower fields and then to the
controller terminals between which is fastened the
resistance coil. The regulator contacts are nor-
mally closed so that the field current passes through
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^
CONTROLLING DEVICES
5 JLICMT 4WITCH I
159
ARMATURE.'
,cmp\^NO^
REGULATOR & CUTOUT
CUT-OUT POINT*
•CRICS WIND
SHUNT WINOINQ
RtaULATOR P0INT5
nCLO RCSISTAtlCC
PfELO
>4RnATURC /
^STARTING MOTOR
STARTING SWITCH
Figure 74. — Controller Connections with Lamp Load Through Wind-
ings (Gray & Davis).
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160 STARTING AND LIGHTING
them and by way of the wire back to the negative
brush.
Current for the shunt winding on the controller
magnet enters the controller through the grounded
terminal, passes through the magnet winding and
then through the controller terminal A to the negative
brush. The positive brush is grounded so that the
magnet circuit is completed, and the cut-out contacts
will close when the dynamo voltage is high enough.
The path of the changing current is from the posi-
tive brush to ground and from ground to the battery.
After passing through the battery, this current flows
to the controller terminal B, through the series wind-
ing of the magnet and by way of the closed cut-out
contacts and the terminal A to the negative brush.
The series coil also acts as the regulator winding and
when the amperage has reached the poiiit for which
the adjustment is set, the regulator contacts are
drawn apart. The field current then flows through
the resistance coil and this resistance reduces the
dynamo output. The amperage flowing through the
series magnet winding determines the point at which
the regulator will act and accordingly limits thie
dynamo output.
It will be noted that the lamp circuits are attached
to the controller terminal L, and current for the
lamps must pass through this terminal. With lamps
turned on, the entire flow of dynamo current would
not return through the cut-out contacts to the nega-
tive dynamo brush, but a part of it would leave the
series magnet winding at the point from which a con-
nection leads to controller terminal L, The part of
the current that is thus used for lighting does not pass
all the way through the series winding, and the
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CONTBOLLING DEVICES 161
strength of this winding is therefore reduced in pro-
portion to the current flowing to the lamps. With a
decreased strength of this magnet, the regulator con-
tacts will not open so soon, and the dynamo output will
reach a higher value before the regulator acts. This
additional output compensates in a measure for the
current required for lighting. Devices of similar ac-
tion are used with other makes of equipment, the
application illustrated serving, however, to demon-
strate the principle involved in all of them.
(8) The resistance of carbon is suflSciently great to
make it well suited for use as field resistance. Two
forms of carbon have been used for this purpose, one
being a number of carbon discs, such as found in some
models of U. S. L. and Aplco equipment, and the
other being finely divided, or powdered, carbon mixed
with flake mica, as used with the Bosch voltage
regulator.
Carbon discs are used by carrying them in the form
of a pile laid one against the other. They are nor-
mally held tightly together by the action of a spring,
and in this condition their resistance is very low.
The armature of the regulator electromagnet is at-
tached to the spring bar in such a way that the power
of the magnet acts to release the spring tension. This
will happen when the amperage passing through the
magnet becomes excessive. The carbon discs are
thereby released, and the poor contact between adja-
cent discs interposes a high resistance in the field cir-
cuit, which is completed through the carbon, and the
dynamo output is reduced.
When powdered carbon is used, it is carried in a
cup and is compressed by a plunger. Attached to the
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162 STARTING AND LIGHTING
plunger is a rod that passes through a magnet wind-
ing, and with increase of amperage through this wind-
I ing, and consequent increase of magnet strength, the
pressure exerted by the plunger is released. The
springiness of the flake mica then forces the particles
of carbon apart, and the resistance of the mass is
increased over what it would be in the compressed
state. The field circuit is completed through the car-
bon mass and the plunger is held down by a spring.
When the magnetism overcomes the tension at which
the spring is set the field current is reduced and fur-
ther rise of dynamo voltage is prevented.
All of the carbon resistance systems are adjusted
by changing the spring tension. Increase of spring
tension holds the carbon together until a higher am-
perage or dynamo voltage is reached and decrease of
the tension lowers the output. The U. S. L. controller,
Figure 75, is adjusted by turning a small screw to the
end of which is attached the coil spring that holds the
carbon pile pressure arm. The Aplco controller has
an adjusting screw projecting from the bottom of the
case, while the Bosch controller makes use of an oval
shaped spring whose tension is changed by turning in
or out on a tapered plug that passes over one side of
the spring.
(9) The regulating device for one of the Aplco
systems makes use of an electromagnet whose winding
is connected across the terminals of the battery so
that the magnet increases in strength as the voltage
of the battery increases. The field circuit is com-
pleted through the contacts controlled by this magnet,
and when the battery voltage reaches the point that
corresponds to the tension of the adjusting spring,
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CONTROLLING DEVICES
lOii
V^lgnre 75. — Controller with Carbon Disc Field Resistance (U. S. 2
i64 STARTING AND LIGHTING
the contacts open and, except for that passing through
a resistance coil, prevent further flow of current
through the shunt field of the motor-dynamo. This
stoppage of the field current prevents further charge
of the battery until its voltage falls.
(10) The controller used with Adlake equipment
carries a rheostat which is controlled by the action
of a plunger passing through the center of a magnet
winding. See Figure 76. The rheostat consists of an
arm pivoted at one end and carrying a carbon brush
at the other end. This carbon brush travels over a
series of contact segments as the arm moves up and
down. One end of the field circuit is attached to the
sliding arm and the other end to one end of the series
of segments. Between each pair of adjacent segments
is placed a small coil of resistance wire, and with the
end of the arm resting on the contact segment farthest
from the one carrying the end of the field circuit, it
will be necessary for the field current to pass through
each of the resistance coils in fiowing from the arm to
the end of the field circuit that attaches to the seg-
ments. With the arm resting on the segment to which
is attached the end of the field circuit, the field cur-
rent does not have to pass through any of the resist-
ance coils. This latter position is the one assumed by
the arm with the. dynamo idle or running at very low
speeds.
The entire dynamo output passes through a magnet
winding and inside of this magnet winding is placed
an iron plunger. This plunger is supported by a
small cable that passes around a pulley attached to
the sliding arm pivot, and as the plunger is drawn
into the coil by increase of magnetism and amperage.
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CONTROLLING DEVICES
165
O ♦oo -oO ♦b4
o
O
o
o
"H
O
Figure 76. — Controller with Solenoid and Field Rheostat (Adlake).
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166
STARTING AND LIGHTING
the arm is caused to travel over the segments and
thus place additional resistance in the field circuit.
The dynamo output is altered by changing the weight
carried by the plunger. Increasing this weight will
raise the dynamo output, while decreasing it will lower
the output.
Figure 77. — Controller UslDg Mercury- Well Principle (Delco).
A — Magnet Winding. D — Plunger Rod in Mercury
B — Plunger Cylinder. Well.
C — Plunger Core. 1 — ^Fleld Circuit Connection.
(11) A number of Delco systems have been fitted
with a regulator known as the ** mercury well'* type.
See Figure 77. This regulator includes a tube made
from insulating material and carrying a coil of re-
sistance wire wound around it. The lower end of
this coil of wire dips into a well, or pocket, in which
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CONTROLLING DEVICES 167
is carried a quantity of mercury. The field circuit is
completed through the resistance wire and the mer-
cury, one end of the field circuit attaching to the wire
and the other end to the mercury well. With the
dynamo idle or running at low speeds, the plunger
tube drops down into the mercury so that the field
current does not have to flow through a great length
of the coil, but passes directly into the mercury
and through the well with its comparatively small
resistance.
Around the upper end of the tube is placed a mag-
net winding, and the upper end of the tube forms
an iron plunger. The magnet winding is attached
between the dynamo brushes, and with increase of
dynamo voltage, the strength of the magnet winding
is increased. This magnetism will finally lift the
resistance tube so that a greater length of the wire is
held up out of the mercury. The field current is re-
duced by flowing through this additional resistance,
and the dynamo voltage is prevented from rising
above a predetermined point. The voltage is adjusted
by changing the resistance in the magnet circuit
either by means of a small lever on the regulator or
by placing a connecting link of high or low resistance
between regulator and cut-out, a higher resistance
allowing an increased voltage.
(12) A method of regulation rarely used has been
employed with some of the older models of Deaco
equipment. These dynamos carry permanent field
magnets, and in connection with these magnets, have
a sfet of shunt field coils. An electromagnet is car-
ried underneath the arch of the permanent magnets,
and by opening and closing contacts with increase of
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168 STARTING AND LIGHTING
dynamo output flowing around the magnet winding,
the following action takes place :
At low dynamo speeds the shunt field windings
assist the permanent magnets and a relatively high
output is maintained. With increase of speed and
voltage, the shunt field circuit is opened and the per-
manent magnets act alone, the loss of the field winding
strength serving to counteract the increased .speed.
With a still further increase of speed, the circuit is
completed through the shunt field windings, but with
the current flowing in silch a direction that the wind-
ings oppose the permanent magnets. At this time the
fleld current flows through a length of resistance wire.
At the highest dynamo speed the resistance is removed
from the shunt field circuit and the full field strength
opposes the magnetism of the permanent magnets.
The steadily increasing dynamo speed is opposed more
and more by the decrease in strength of the fields, and
the output of the dynamo is held at practically a
constant value.
(13) The voltage acting on the field circuits of a
shunt wound dynamo is primarily determined by the
speed of armature rotation. If this speed were to be
kept constant, and at the same time the resistance
through the outside circuits were to remain prac-
tically constant, the dynamo voltage would remain at
the same point. This effect is secured in som6 systems,
notably in a lai^e number of Gray & Davis dynamos
made previous to 1915. Dynamos of this make and
with this type of regulation have, also a compound
field winding through the series coils of which the
lamp current passes as described under (3) in this
chapter.
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CONTROLLING DEVICES
169
The armature shaft is not connected directly with*
the engine, but is fastened instead to a framework
that carries two friction shoes. See Figure 78.
These shoes are held in contact with the inner surface
of a cylindrical drum, or in some cases, the shoes are
replaced with a flat disc and this disc is held in contact
with a similar disc by the tension of adjustable
springs. The drum, or the second disc, is iattached to
the dynamo drive shaft and as long as the two parts,
shoes and drum or discs, are^ held together, the arma-
Fig. 78. — Friction Clutch for Limiting Dynamo Speed (Gray ft
Davis).
ture shaft will be driven at the same speed as the
drive shaft. Therefore, as long as the two driving
parts are together the dynamo speed will rise and
fall in direct ratio to the engine speed. Two governor
weights are fastened to the armature shaft and revolve
with it. The arms carrying these weights are at-
tached to the shoes or to the movable disc in such a
way that when the weights are caused to fly apart by
centrifugal force the shoes are drawn away from the
drum or the discs are drawn apart. The driving parts
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170 STARTING AND LIGHTING
are normally held together by coiled spring^, and
when the pull of the rapidly revolving weights is suf-
ficient to overcome the tension of these springs, the
armature shaft is released from the driving shaft and
the speed of the armature will not be increased above
this point.
The dynamo voltage and output is changed by
changing the tension on the governor spring or
springs. Increasing the spring tension will cause the
armature shaft to remain connected to the driving
shaft until a higher speed is reached and the output
will show a corresponding increase. Decreasing the
Figure 79. — Friction Clutch for L»lmiting Dynamo Speed (Auto-
Llte).
spring tension will prevent the armature from re-
volving at such a high speed and the output will be
reduced.
(14) A form of governor operating on the same
principle as the one just described has been used witli
older models of Auto-Lite dynaim)s. See Figure 79.
The governor consists of a drum fastened to the driv-
ing shaft and of two shoes, each one attached to a
weight and held in contact with the drum by the ten-
sion of a spring. In this case the spring tension is
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CONTROLLING DEVICES 171
not changed, but dynamo output is altered by moving
the weights on their supporting arms. The weights
are held in place by screws, and as the weights are
moved farther from the pivotal point of their re-
spective arms, they produce a releasing eflfect at a
lower speed and consequently reduce the dynamo out-
put. Moving the weights in on the arms increases the
dynamo voltage and output. Dynamos that are fitted
with this form of regulation and of Auto-Lite make
are fitted with permanent field magnets.
(15) One other application of the centrifugal gov-
ernor has been used, this being the system applied to
certain models of Vesta dynamos. These* machines
use permanent field magnets, and the regulator is
carried at one end of the dynamo housing. The gov-
ernor weights are attached to a sliding ring, and as
this ring moves along its shaft under the action of
the flying weights, it compresses an adjusting spring.
Attached to the sliding ring is an arm whose outer
end travels over a rheostat. This rheostat consists of
a number of segments, the end one being disconnected
from all wiring and each pair of the remaining seg-
ments carrying a coil of resistance wire between them.
With the dynamo idle, or running at very low speeds,
the end of the arm rests on the segment that has no
connection. The charging circuit is attached to this
arm, and When the end of the arm is on the discon-
nected segment, the dynamo is disconnected from the
battery. This part of the governor acts as a cut-out.
As the arm travels over the segments with increase
of armature speed and centrifugal force from the
weights, a continually increasing number of resist-
ance coils is inserted in the charging circuit and an
excessive battery charge is thereby prevented. The
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172
STARTING AND LIGHTING
time of cutting in and out as well as the dynamo out-
put is adjusted by changing the tension of the gov-
ernor springs. There are two springs, one acting to
regulate the time of cut-but action and the other being
for output regulation.
CONTHOIXCIt
•wi-roN
Hr-si .fsd ♦j -sf ♦rsj
Figure 80. — Connections for Ampere-Hour Meter Regulator (Delco).
(16) The first Delco systems to be used during
1912 and 1913 were equipped with an ampere-hour
meter that measured and indicated the number of
ampere-hours that passed into or out of the battery.
This meter, Figure 80, is attached in such a way that
all of the current entering the battery from the dy-
namo causes an indicating hand to travel in a counter-
clockwise direction, while all current leaving the bat-
tery for lighting, starting and other purposes causes
the hand to travel around its dial in a clockwise direc-
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CONTEOLLING DEVICES 173
tion. Carried in the meter case is a set of contact
points through which the field current must pass, and
movement of the meter past a certain position causes
first one pair of contacts to open, and with further
travel in the same direction during battery discharge,
causes the other set of contacts to separate. With the
first set of contacts open, the field current must pass
through a length of resistance wire, thus reducing the
field strength and charging current. When the sec-
ond set of contacts open, the field circuit is opened
altogether and further charge is stopped because there
is practically no field strength.
As the battery continues to charge without a pro-
portionate discharge the meter hand comes around to
a point at which the first set of contacts will open.
Should the use of the car go on without calling for
any considerable discharge from the battery, the
meter hand will finally travel to a position that will
open the second set of contacts and the charge will
be stopped. If now the battery current be used, the
meter hand will revolve in the opposite direction and
the second set of contacts will close. The dynamo
will then start to generate current at a low rate be-
cause of the completion of the field circuit through
the resistance wire. With further net discharge of
the battery the first set of contacts will close and the
dynamo charge will reach its full value. With this
system in operation it is necessary to move the hand
in the direction of discharge at intervals of about two
weeks because of the fact that a storage battery must
have a greater number of ampere-hours charge than
discharge. The meter hand is held in place by a
toothed joint, and by lifting it up, it may be reset to
give the necessary additional charge.
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174 STARTING AND LIGHTING
It should be noted in connection with the adjust-
ment of regulating devices and the consequent chang-
ing of dynamo outputs that this is necessary only
under exceptional conditions. The adjustment made
by the manufacturers of the car or of the electrical
equipment is correct for that car under average con-
ditions, and it should never be altered until the per-
son doing the work is sure of reasons sufficient to war-
rant the change. It will usually be found that low
dynamo outputs are due to lack of proper care in
cleaning brushes and commutators, in keeping wire
connections clean and tight and in keeping the bat-
tery clean and filled with pure water.
It is, however, possible that unusual conditions of
service may call for a change in dynamo output. For
instance, a car that is driven mostly at night with the
lamps lighted may require that the dynamo have a
greater output than for one that is driven under
usual conditions. The addition of electrical acces-
sories sufficient to make a load on the system greater
ithan it was designed to handle is not a good reason
for increasing dynamo output, and doing so under
these conditions will usually result in permanent dam-
age to the electrical equipment.
In some cases the output adjustment is rendered
easy of use by the repairman or driver of the car and
the makers may furnish instructions for altering the
charge rate for different conditions. In other cases,
and the number of these is increasing, the adjustment
is made at the factory, and the parts are then sealed
so that this adjustment cannot be changed without
breaking the seals. In these cases, breakage of the
seals will result in the maker's guarantee becoming
void.
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CONTROLLING DEVICES 175
As a general rule the dynamo output should be
greater in winter than in summer because of the lower
efficiency of the battery and the greater use of the
lamps and starter at this time. During a long tour
it may be advisable to lower the charge rate or to stop
the charge altogether, by short circuiting the dynamo
terminals, by opening a touring switch, if one is pro-
vided, or by removing a field fuse.
Considering the various methods of regulation from
the standpoint of adjustment, the following points
should be noted: It is not practicable to alter the
dynamo outpi^^ when reversed series regulation is
used and this advice applies equally well to machines
having compound field windings. The remaining
classes of inherent regulation may usually be ad-
justed; the third brush by changing thje position of
the brush, and the iron wire system by changing the
size of the wire used.
It is seldom advisable to attempt to make changes
in adjustment of magnetically controlled vibrators
that act to insert and withdraw field resistance, and
in fact these types are not always made with pro-
visions for adjustment. Adjustment is provided on
systems that use carbon field resistance and the meth-
ods of adjustment have already been considered.
The dynamo output of the system that uses an
ampere-hour meter is not directly adjustable, although
the total net battery charge may be increased by mov-
ing the hand so that the contacts are not separated
at such frequent intervals. The adjustment of the
system using the rheostat operated by the plunger and
coil is provided for by changing the weight in the
plunger while a certain adjustment may be secured
with the mercury well regulator by altering the re-
sistance in series with the magnet coil.
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176 STARTING AND LIGHTING
Kegulation depending on the action of centrifugal
governors is always provided with means of adjust-
ment. It should be borne in mind that these adjust-
ments are very delicate and the slightest possible
change in spring tension or weight position will have
a considerable effect on the dynamo output.
Temperature Control. — In order to allow the dy-
namo to furnish a comparatively high rate of charge
during cold weather and at all times while the dynamo
itself is cold the Eemy Electric Company has intro-
duced an auxiliary form of current regulating device
which is acted upon by the dynamo temperature.
A dynamo becomes heated to a degree proportionate
to the amount of current flowing or the amount being
generated. A low output with low amperage flowing
to the battery allows the wiring to remain at normal
temperatures, while higher amperage causes heat to be
generated because of resistance of the wiring. This
change of temperature is made to operate a thermostat
which is carried in the dynamo.
The thermostat bracket carries a small coil of re-
sistance wire and a blade made from a strip of spring
brass welded to a strip of nickel steel. Due to the
greater expansion of the brass this combination will
bend when heated. Mounted on the base is one of a
pair of silver contact points, the other contact being
carried by the blade. The points are held together by
the spring tension of the blade itself as long as the
combination remains at normal temperatures. When
the heat within the dynamo reaches approximately
175° Fahrenheit the bending of the blade causes the
contacts to separate.
The connection of the thermostat in the circuit is
shown in Figure 80a. The resistance coil is connected
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CONTROLLING DEVICES 176a
between the parts which carry the contact points. The
moving blade is connected with the line leading to
one of the dynamo brushes, while the base which carries
the stationary contact is connected with the line lead-
ing to the field windings. With the dynamo cool the
contacts are together and the field current flows at its
full value from the dynamo brush through the closed
TO CENERATOR PIEtO TO OENERATOR PlECD
AAA/WN?'"
PROM GENERATER BRUSH PROM GENERATOR BRUSH
COLD AND CLOSED HOT AND OPEN
Figure 80a. — ^Thermostatic Control.
contacts and to the field, the dynamo giving its normal
output. Generation of heat finally causes the contacts -
to separate and the field current must then take the
path through the resistance to the fields. This inter-
posing of the resistance reduces the flow of field cur-
rent and the output of the dynamo is cut about one-
third until the parts again cool off and allow the con-
tacts to close.
Adjustment or repair of the thermostat should
rarely be attempted, it being more satisfactory to in-
stall a new unit in case of trouble. If the screw by
which the field line is attached should be turned, no
weight or downward pressure should be put on the
screwdriver because the thermostat frame may be bent.
The contact points should never be forced apart as the
blade might be sprung and the action rendered incor-
rect. Should the resistance coil be broken or burned
out the dynamo will generate while cold and as long
as the points remain in contact, but as soon as heat
develops the points will separate and prevent any
flow of field current or any output from the dynamo
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176b STARTING AND LIGHTING
until it cools sufficiently for the points to again close.
Such a condition as that just described will cause
severe burning of the contacts and they may possibly
weld together. Should the contacts remain closed the
dynamo will give its high output continuously and may
thereby cause damage to the battery and the dynamo
itself. A burned out resistance indicates trouble such
as a loose connection, a corroded battery terminal or
an open circuit in the charging lines.
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CHAPTER VI
DBIVE METHODS AND STABTING SWITCHES
With the exception of the type of equipment which
mounts the motor-dynamo directly on the engine
crankshaft, all starting motors and some charging
dynamos require a method of drive that allows their
armature speed to exceed the speed of the engine
crankshaft. * This reduction is eflfected in the connec-
Figure SI. — External Armature and Fields for Motor-Dynamo
(U. S. L.).
tions between engine and electric unit and may take
any one of a wide variety of forms.
Mechanically speaking, the simplest possible drive
is that used by the U. S. L. equipment. The electric
unit, Figure 81, is a large size ring armature type of
motor-dynamo having the armature fastened securely
to the engine crankshaft. In some of the older types
the armature revolves inside of the field coils, while
177
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178 STARTINa AND LIGHTING
in later models the armature diameter is great enough
so that it is carried outside of the fields. In all cases
the armature revolves and the fields are stationary.
This machine acts as a compound-wound starting
motor when the starting switch is closed. When the
engine has started and is running under its own
power the speed of the motor-dynamo armature be-
comes great enough to generate a voltage in excess of
that of the battery, the electromagnetic cut-out closes
and battery charging commences. The motor-dynamo
is carried inside of the flywheel housing and the start-
ing switch may be mounted on this housing or at some
other point on the car. The regulating device and
cut-out, or else a separate electromagnetic cut-out,
will be found on the cowl or dash of the car.
A very common method of drive for eitiier dynamo,
motor or motor-dynamo is through straight spur or
helical gearing from the engine timing or ignition
drive gearing. In this case the electrical unit is
mounted and driven in much the same way as em-
ployed for magneto drives and in mai^y cases is
driven by the same shaft that drives the magneto.
The water pump shaft, when a pump is used, forms a
convenient method of drive for the electric machine
and this shaft is often used by mounting the motor
or dynamo at the end of an extension from the shaft
passing through the pump.
A satisfactory connection and a simple application
is secured by connecting the electric units to the
engine crankshaft by means of a chain of either the
roller or silent type. The crankshaft sprocket may be
at either end of the engine, although the front or
starting crank end is usually used. In some cases the
drive chain will be enclosed and possibly lubricated
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DRIVB METHODS AND STARTING SWITCHES 179
from the timing gear or crankcase compartment of
the engine. In other applications the chains remain
exposed and in plain sight.
Chain drive, gear drive or direct drive on the crank-
shaft may be utilized for either dynamo or motor
because tiiese types are well suited to carry loads as
great as those imposed in engine starting and provide
a positive connection. Drive methods that depend on
friction between two surfaces can only be used for
dynamo work because of the fact that they would not
have sufficient surface available on an automobile to
carry the power delivered by the motor in cranking.
Belt drives have been used and are now used by a
limited number of makers, and are satisfactory in all
ways as long as the belt is kept tight enough to prevent
excessive slippage and as long as both belt and pulley
surfaces are kept clean and smooth. Dynamos have
also been driven by means of a friction clutch, this
application being made with the Entz motor-dynamo
used on some models of White cars. With such a
clutch in use sudden acceleration of engine speed does
not place severe strains on the motor-dynamo drive
parts.
A distinctive form of motor-dynamo drive has been
used with a great many applications of the Delco sys-
tem (Figure 82), this method allowing the motor-
dynamo armature to run at a greater speed during
engine starting than while generating current, yet pro-
viding a positive drive in each case. The single arma-
ture of the motor-dynamo has an extended shaft at
each end. At the rear end this shaft extension carries
one of a train of gears that mesh with teeth cut on the
rim of the flywheel. With this flywheel gearing in
mesh and with the motor-dynamo operating as a
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180
STARTING AND LIGHTING
starting motor, the gear reduction is about twenty to
one. The front end extension of the armature shaft is
driven from another shaft, which is in turn driven
from the front end of the engine crankshaft by means
of gearing or chains. The connection from the front
end of the armature shaft to the driving shaft is made
through an overrunning or one-way clutch. This
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DRIVE METHODS AND STARTING SWITCHES 181
shaft and clutch will drive the armature shaft hetween
two and one-half and three times as fast as the engine
crankshaft runs, and as long as the armature shaft
has no tendency to ran faster under its power as a
starting motor, the clutch^ will hold. Whenever the
battery current is sent through the motor-dynamo, the
armature shaft begins to turn and the overrunning
clutch releases so that the armature shaft runs at the
starting speed.
DRIVE RATIOS
Large dynamo output may be secui^ed in either of
two ways, high speed or lai^ size. It is manifestly
not practical or desirable to use dynamos of large size
on automobiles because of the excessive weight and
greater cost. The alternative of comparatively high
speed is therefore resorted to. Dynamos generally are
operated at from one to four times engine speed, the
most common ratios lying between two to one and
three to one. With a rear axle gear ratio of four to
one and with thirty-four-inch diameter road wheels in
use, the engine crankshaft will turn about forty revo-
lutions per minute for each mile per hour of car speed.
Therefore, at a car speed of fifteen miles per hour, the
crankshaft will be revolving at about 600 revolutions
per minute ; at a car speed of twenty miles per hour,
the crankshaft speed will be about 800 revolutions per
minute, and so on for various car speeds. The types
of dynamos in general use do not deliver their maxi-
mum or rated amperage at armature speeds much
below twelve to fifteen hundred revolutions per min-
ute, and it is desirable that this maximum output take
place at driving speeds of about twenty miles per hour.
It will be seen that in order to drive the armature at
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182 STARTING AND LIGHTING
the required speed with the crankshaft running^ at
about 800 revolutions per minute, a ratio of one and
one-half or two to one will be required.
The conditions governing the selection of a starting
motor drive ratio are the power that the motor will
deliver at its armature shaft, the power required to
start the engine crankshaft and engine parts in motion,
and the power required to keep the crankshaft rotat-
ing at a speed sufficiently high to cause good carbure-
tion and ignition. The engine conditions, in turn,
depend on the bore and stroke of the cylinders, on
the number of cylinders and on the excellence of
design and workmanship in the engine. The power
delivered by the starting motor depends on the amper-
age and voltage of the current flowing through it, on
its speed of rotation, and on the excellence of work-
manship and material. Power required by, or deliv-
ered from, rotating shafts is usually measured in
foot-pounds, one foot-pound being the power required
to lift a weight of one pound through a distance of
one foot.
From three to four times as much effort is required
to start an average engine from rest as is required to
keep it in motion after being started, and the maxi-
mum power that the motor will deliver must be
selected with the starting torque in mind. The word
** torque'' means a twisting or turning force, and as
the powers, being dealt with here are of this class,
the measurements can most conveniently be given in
this way.
The number of foot pounds torque required by
several commonly found sizes of engine is given in the
following table and will give a good idea of the work
that the starting motor is called upon to do.
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DRIVE METHODS AND STARTING SWITCHES 183
No. of Ruiming Starting
Bore
Stroke
Cylinders
Torque
Torqu
3%
4
4
20
82
3%
6%
4
34
125
31/4
41/2
6
25
95
3H
. 51/4
6
32
120
3%
51/4
6
40
140
4
51/2
6
43
155
5
7
6
88
245
3y4
5y4
8
35
130
3
5
12
45
156
While the engine specifications selected in the table
are those of well-known makes of cars, this has been
done only for the . comparative value of the figures,
and does not necessarily represent the exact condi-
tions that would obtain with a certain engine of a
given make because of the variables in manufacture.
Depending on the size and design, typical starting
motors will deliver from three to eleven foot-pounds
torque with current flow between two and three hun-
dred amperes. Taking an average case of a starting
motor capable of delivering six foot-pounds torque,
it will be seen that for the medium-size engines listed
in the table, the gearing must provide a reduction
of from seventeen to one up to twenty-five to one in
order that this six pounds torque at the armature
shaft may be multiplied to produce the 100 to 150
pou^ds torque required to start these engines from
rest. It will be found that a majority of starting
motors in use are provided with reductions that fall
between these two limits.
From the running torques given in the table it will
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184 STARTING AND LIGHTING
be seen that the average engines will require from
twenty-five to forty-five foot-pounds of torque to
keep them in motion. If a gear reduction of twenty
to one is selected, the torque required for running will
be divided by this reduction so that the starting motor
will only have to deliver between one and one-quarter
and two and one-quarter foot-pounds at the armature
shaft after the engine has been started. The amperage
required to accomplish this will be much less than that
called for in starting from rest, and with starting
motors of usual design will range from sixty to one
hundred and fifty amperes. This amperage will allow
the starting motors to attain armature shaft speeds
of from 1200 to 3000 revolutions per minute. These
speeds, with the reduction of twenty to one, will give
a running speed for the engine crankshaft of from
sixty to one hundred and fifty revolutions per minute.
The speed required will vary with different engines,
and it will be necessary to select a starting motor that
will attain the required speed through the gear reduc-
tion in use while developing sufficient power to keep
the engine in motion at that speed. Crankshaft speeds
between seventy-five and one hundred and fifty revo-
lutions per minute are satisfactory in practically all
cases, although engines are driven at higher speeds
in many installations.
The drive ratios selected for use with motor-dyna-
mos do not depfend on the same factors as those for
separate units, because of the fact that the machine
must usually operate at the same ratio for generating
current as for starting the engine. As a general rule
the armature shaft is made to revolve from two and
one-half to five times as fast as the crankshaft. The
power of the motor-dynamo as a starting motor must,
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DRIVE METHODS AND STARTING SWITCHES 185
therefore, be considerably greater for a given speed
than that of separate units.
Various combinations of chains and gearing are
used to obtain the necessary ratio of speed between
the starting motor armature and the engine crank-
shaft. In the case of installations driving to the
crankshaft direct, some form of double reduction will
generally be used with separate starting motors, be-
cause in order to secure a ratio as great as twenty to
one, or even ten to one, with a single reduction, the
size of the driven gear or sprocket would be excessive.
In order to use a single pair of gears or sprockets and
obtain a ratio of twenty to one with all armature
shaft gear or sprocket one and one-half inches in
diameter, the driven member would have to be twenty
times this diameter, or thirty inches, which would, of
course, be impossible to use. To overcome this diffi-
culty, a double reduction system is used with which
a part of the total reduction is taken care of in each
set of gears, or part in a set of gears and the remain-
der by chains with sprockets of different sizes.
When it is realized that two separate reductions of
four to one will give a total reduction of sixteen to
one, the problem is seen to be simple of solution, and
the drive parts will be of very moderate diameter and
still secure the desired ratio of drive. (See Figure
83.) When such a double reduction is used with
chains for the final drive to the crankshaft, the pri-
mary reduction gearing is usually carried on or in
the starting motor housing, one side being connected
to the armature shaft and the other side to the
sprocket on the outside of the housing to which the
chain attaches.
Double reduction systems may consist of sets of
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186 STARTING AND LIGHTING
/
spur gears very similar to those uaed in the change
speed gearing of the car, and in some applications,
notably older models of the Wagner systems, plan-
etary forms of gearing have been used successfully.
The ratio that corresponds to low speed in driving a
car is then used for starting purposes, while the direct
drive is used when the machine acts as a dynamo —
the equipment in question being a single armature
motor-dynamo. A number of makers have used a
small spur gear running inside of a large ring gear
KSD
Figure 83. — Single Reduction (Left) and Double Reduction (Right)
Giving Same Drive Ratio.
with internal teeth. Thjs method gives a great reduc-
tion in speed within a small overall space.
A single reduction is oftentimes used when the gear
on the armature shaft drives to teeth cut on the rim
of the flywheel. With a flywheel seventeen inches in
diameter and an armature shaft gear one and one-
half inches in diameter, the reduction will be approxi-
mately twelve to one, which will answer in almost
all cases. Even with flywheel gearing the double
reduction system is often used, the primary reduction
being much the smaller of the two and taking place
in gearing carried in or near the starting motor
housing. This is shown in Figure 82.
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DRIVE METHODS AND STARTING SWITCHES
187
While the drive to the flywheel or a drive to the
engine crankshaft is the method usually employed for
the starting motor, other systems are also in use. In
the ease of machines known as ** double-deck/' with
the starting motor mounted above, below or at one
side of the dynamo, the drive from the starting motor
armature shaft to the main drive shaft, through which
the engine drives the dynamo, provides a reduction
Figure 84. — Drive Parts for Double-Deck Motor and Dynamo (Gray
& Davis).
that allows the starting motor to operate at six or
more tim& the speed of the dynamo shaft, which,
with the generally found dynamo reduction of two
to one up to three to one, will provide a total reduc-
tion of from twelve up to twenty to one. (See Fig-
ure 84.)
The starting motor does not always drive direct
to either the engine crankshaft or to the flywheel, but
may be so <jonnected that it drives first into the trans-
mission or clutch shaft. With the clutch engaged, the
countershaft in a sliding gear transmission will revolve
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188 STARTING AND LIGHTING
and be positively connected to the engine whether the
gearing is in any one of the forward or reverse speeds
or is in neutral. In some applications the starting
motor is carried on the transmission housing or along-
side of the housing, and drives through gearing to
the transmission countershaft, thence through the
clutch to the engine. This method allows of locating
the starting motor in a convenient place when the
room under the engine hood is so limited that mount-
ing there wpuld prove difl&cult.
Another method of starter drive is that found with
a worm gear drive from the starting motor to the
clutch shaft between the clutch or flywheel and the
transmission housing. By placing the starting motor
transversely across the length of the car, a worm
fitted to its armature shaft may be made to drive a
worm gear fitted to the clutch shaft, and inasmuch as
•worm gearing may be built to give a very great
reduction in speed, a suitable drive is secured by
means of a single reduction.
DRIVE METHODS
In order to allow separate starting motors to drive
the engine during cranking and then to be released
so that they are not driven at excessive speeds by the
engine, a number of exceedingly ingenious devices
have been used. It is not uncommon for the gasoline
engine to operate at crankshaft speeds as high as
2000 revolutions per minute. With a positive con-
nection between starting motor and engine, and a
gear reduction of twenty to one, this would cause
the starting motor armature to revolve at 40,000
revolutions per minute, which is, of course, impos-
sible, because the centrifugal force acting on the
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DRIVE METHODS AND STARTING SWITCHES
189
armature would destroy the motor long before any-
such speed could be attained, even were the e^igine
capable of furnishing sufficient power to do the work.
Bendix Screw. — ^A very commonly used system is
that known as the Bendix drive or inertia pinion
(Figure 85). By this method the armature shaft
gear is automatically meshed with teeth on the fly-
wheel as soon as the motor armature shaft starts to
revolve, and then, as soon as the engine speed is high
enough for the flywheel rim speed to exceed that of
Figure 85. — 'Bendix Drive; Screw, Spring and Pinion.
the armature shaft gear, the gear is instantly thrown
out of mesh. Surrounding the extended armature
shaft is a sleeve free to move on the shaft but con-
nected to the shaft through a coiled spring having
one end fastened to the armature shaft and the other
end fastened to the sleeve. On the outside of this
sleeve is cut a coarse multiple screw thread, and a
small gear with a correspondingly threaded -hub is
carried by the sleeve. As the shaft is turned, the gear
will travel back and forth along the threaded sleeve
just as a nut would travel along a bolt if the bolt
were turned while the nut remained stationary. The
starting motor is mounted in such a position that the
sleeve gear is in mesh with teeth on the fljrwheel rim
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190 STARTING AM) LIGHTING
when it is at (me end of the threads, and is completely
out of mesh with the flywheel when at the other end
of the threads.
With the engine and starting motor idle, the small
gear is out of mesh with the flywheeL Jnst as soon
as cunent is sent throng the motor the armature
shaft turns and, through the coiled upring^ causes
the sleeve to turn. On one side of the gear is a
weighted flange, and because of this weight the gear
does not commence to revcdye. at once, but rather
travels along the threads of the screw on the sleeve.
This action brings the gear in mesh with the teeth
on the flywheel either instantly, or, if the teeth meet
end-on and do not slide into mesh, the coiled spring
allows the sleeve to turn on the armature shaft
enough to bring the teeth into positi<Mi for meshing.
When the small gear has traveled far enough on
the threaded sleeve to be in full mesh with the fly-
wheel teeth, one side of its hub has come against a
shoulder on the sleeve and it can travel no farther.
The gear must then revolve with the sleeve, and be-
cause of the resistance of the flywheel to motion,
the spring coils tighter still. When the spring is
tightly coiled, the full power of the starting motor,
together with the power stored in the coiled spring,
acts to place the flywheel in motion, and the engine
is cranked by the starting motor until it starts and
runs en its own power.
As soon as the engine starts, the speed of the rim
of the flywheel causes the small gear to revolve much
faster than the starting motor has been driving it,
and because it travels faster than the motor shaft
and sleeve, it begins to travel along the threads in
a direction that takes it out of mesh with the fly-
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DRIVE METHODS AND STARTING SWITCHES 191
wheel teeth. This change of direction is brought
about because when the motor first started, the arma-
ture shaft and sleeve traveled faster than the small
gear, while now the small gear is traveling faster
than the armature shaft and sleeve. This action
sends the gear out of mesh without causing the start-
ing motor to attain any excessive speed. Should the
starting switch be again closed .with the engine run-
ning, the small gear will travel toward the flywheel
and strike the rapidly turning teeth on the flywheel,
and its speed will thereby be increased to such an
extent that it again travels away from the flywheel.
The weight on one side of the small gear that acted to
prevent the gear from revolving with the threaded
sleeve now performs another important function by
making the gear bind on the threads through the
overbalancing action of the weight on one side. This
binding prevents the gear from again meshing with
the flywheel teeth.
Overrunning Clutch. — In a large number of sys-
tems the starting motor drives the engine through an
overrunning clutch that will allow the starting motor
to drive the engine shaft as fast as it is capable of
doing, but will allow the clutch to release whenever
the engine tends to drive the starting motor. The
principle involved is similar to that used in th^
bicycle coaster brake in which the rider (represente4
by the starting motor) might pedal the bicycle as fast
as he possibly could, but with which no speed of the
bicycle (represented by the engine) could cause the
rider to pedal faster. In fact, the rider could stop
pedaling altc^ether and allow the bicycle to run, just
as the starting motor can come to rest and allow the
engine to run.
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192
STARTING AND LIGHTING
The eonstruction of an overrunning clutch is shown
in Figure 86. The clutch consists of two principal
parts, the outer ring A and the clutch center B.
Figure 86. — Overrunning Clutch.
A — Driving Ring. P — Plunger.
B — Inner Member, R — Roller.
C— Driving Pinion. S — Plunger Spring.
D — Driven Shaft.
The outside circumference of the ring A carries gear
or chain teeth or a drive shaft, and is driven from
the starting motor. In the construction shown, the
starting motor drives the ring in the direction of the
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DRIVE METHODS AND STARTING SWITCHES 193
arrow. At several points around the inner part of
the clutch are slots in which rollers are placed. The
roller is continually pressed against one end of the
slot by the small plunger and spring, and it will be
seen that rotation of the outer ring in the direction
of the arrow wiU wedge the roUers between the ring
and the center part of the clutch. With the rollers
thus tightly binding the two parts together, the inner
part will be rotated by the ring and in the same direc-
tion as that of the ring. The center part of the clutch
is fastened to the shafting or gearing that cranks the
engine.
With the power of the starting motor applied to
the pinion C, the outer ring and center section will
turn together just as soon as the rollers lock in place.
The locking is practically instantaneous, so that crank-
ing commences at once. The starting motor will con-
tinue to revolve the engine crankshaft until the igni-
tion takes place and starts the engine under its own
power. The engine will now drive the center of the
clutch in the same direction as during the cranking
operation, but, of course, at a much greater speed.
The center part of the clutch now rotates much faster
than the ring, and, in fact, the ring and starting
motor can stop entirely because of the fact that rota-
tion of the center part in the direction of the arrow
tends to roll the rollers back toward the plunger and
spring end of the slot, thereby allowing clearance and
release of the wedging action between the two parts
of the clutch. No amount of power applied to the
center of the clutch so that it rotates in the direction
of the arrows will cause the rollers to wedge, and the
engine can increase in speed without any effect on
the starting motor.
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194
STARTING AND LIGHTING
Bushmore Starting Drive, — ^A novel system of gear
meshing is shown in Figure 87, this being the method
applied to Rnshmoi* and Bosch-Rushmore systems.
In the idle position shown at 1, the armature of the
starting motor is held out of line with the pole pieces
by the coiled i^pring 8. On the opposite end of the
armature shaft is carried the small spur pinion which
will mesh with the ring gear F on the flywheel. The
Figure 87. — Gear Meshing of Rushmore Starting Motor.
starting switch has two active contacts, which are
made, one after the other, when the switch button or
handle is moved. On the first contact the battery
current flows through the fields and causes their cores
and pole pieces to become strong electromagnets which
act on the iron of the armature core to draw the arma-
ture with its shaft and the spur pinion quickly and
powerfully to the left, thereby meshing the pinion
with the flywheel gear. During this first contact a
resistance is in the starting motor circuit so that but
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DBIYB METHODS AND STARTING SWITCHES 195
a part of the full battery current can flow, and most
of this current passes through the fields only, because
of a low resistance by-pass for the armature current.
The small flow through the armature causes its shaft
and the pinion to rotate slowly so that the meshing
of the gears will be accomplished without trouble.
The pause on this flrst switch contact is just long
enough to allow gear meshing, and then the full bat-
tery voltage and current is applied to the starting
motor through the second contact, which cuts out the
resistance and armature current by-pass. Cranking
then takes place, and as soon as the engine t^es up
its cycle of operjation, the flywheel gear rotates the
small pinion at a high rate of speed. This high speed
causes the motor to becomie momentarily a djniamo,
with the result that at the moment when it generates
battery voltage, there is no further flow of battery
current through the motor. With no flow in either
direction, the fields are demagnetized and the tension
of the coiled spring throws the gears out of mesh.
Thereafter, the small flow of current that would be
required to keep the armature in motion, should the
starting switch remain closed, is not sufficient to
draw the armature endwise and mesh the gears again.
Westinghouse Magnetic Gear Shifts, — ^In addition
to a mechanically operated system and other applica-
tions using the Bendix screw, Westinghouse equip-
ment has been furnished with gear-shifting devices
and starting switches operated by powerful electro-
magnets or solenoids (Figure 88). Passing through
the starting motor armature shaft is a sliding rod
which carries the spur pinion for flywheel meshing
at one end and the core of a solenoid winding at the
other. This rod is free to slide endwise, but must
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196
STARTING AND LIGHTING
turn with the armature shaft. In series with the
starting motor circuit is the winding of the solenoid,
and when the current for the starting motor passes
through the winding the core is pulled back, with the
result that the spur pinion, which has helically cut
teeth, is meshed with the flywheel gearing. The gears
are normally held out of mesh by a coiled spring, and
when the pull necessary to start the engine is no
ElKln-Magnetic
^Mrting Switch.
Starrin g Mag net^Siorting Motor
ngnre 88. — Ma^etic Starting-Gear Meshing System (Westing-
house).
longer required, the solenoid is demagnetized to such
an extent that this spring pulls the gears out of- mesh.
Double Bediiction Systems, — ^A system of gear-mesh-
ing which has been very generally used with slight
modifications by a number of makers is illustrated in
Figure 89. The starting motor M has its armature
shaft keyed and extended at D. The pinion P may
slide along this shaft, but turns with it because of
the squared construction. Pulling the rod R in the
direction of the arrow will slide the pinion P into
mesh with the flywheel ring gear F by means of the
yoke Y. At the samje time that the gears are fully
meshed, the starting switch contact piece will have
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DRIVE MBTHODS AND STARTING SWITCHES
197
closed the circuit between the contacts 8, being moved
by the arm A. The starting motor will then crank
the engine in the usual way. An overrunning clutch
is usually incorporated in the starting motor housing
or in an intermediate gear between armature shaft
and the pinion P.
In case the gear teeth should met end on, they would
not mesh, and the following action would take place :
Figure 89. — Starting Drive with Spring Release.
R — Starting Pedal Rod.
S — Release Spring for Pinion
Yoke.
S' — Switch Contacts.
Y— Gear Shifting Yoke.
A — Moving Contact of Switch
D — Motor Armature Shaft.
F — Flywheel.
M — Starting Motor.
P — ^Motor Pinion.
The rod R is free to slide through the upper end of
the yoke ¥, except for the action of the coiled spring
8, which holds the yoke against the collar shown
on R and just at the left of Y. If the rod is pulled,
the pinion P will first come up against the flywheel
gear F, and then if P and D can move no farther,
the coiled spring will be compressed against Y. Be-
cause of the fact that the rod R is moving regardless
of the yoke, the arm A will cause the contact piece
of the starting switch to close the circuit and the
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198
STARTING AND LIGHTING
starting motor will commence to revolve. The small-
est part of a revolution of the armature shaft will
bring the gear teeth into meshing position, and the
tension that has been placed on the spring 8 by the
continued movement of the rod B will instantly snap
the pinion into full mesh with the flywheel gear,
and cranking will take place.
In the system just described, 'power is not applied
to the starting gearing in any wtiy until the gears are
(
tri
= flywheel
Figure 90. — Starting Switch with Resistance.
P, P' — Preliminary Contacts. R — Resistance.
Q— Main Contacts.
fully meshed or until the spring has been sufficiently
compressed to mesh the gears instantly with the first
application of power. Another method which will
be found in a. number of applications causes the
pinion to revolve quite rapidly, but with very little
power, so that the moving teeth will quickly find
a meshing position with those on the flywheel rim.
A system of this type, in which power is momentarily
applied to the pinion and then withdrawn, is shown
in Figure 90. The starting switch now has two pairs
of contacts, P and PS and Q. Between the contacts
P and ^ is a resistance -B. The pinion is normally
held out of mesh with the flywheel teeth and in the
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DRIVE METHODS AND STARTING SWITCHES 199
position shown. When the starting switch button is
pressed down, the pinion is moved toward the fly-
wheel, but before the teeth are in a meshing position
the starting switch contacts P and P^ are connected
by the moving contact piece on the switch rod. Bat-
' tery current then flows through the motor and to the
switch contact through the resistance, which reduces
the flow of current, and by way of the contact P,
contact piece and contact P^, to the wire and back
into the battery. The armature shaft and pinion are
then revolved at high speed with little power, and as
the switch rod continues to move the pinion toward
the flywheel, the contact piece in the switch leaves
the contacts P and P^, so that the pinion is left spin-
ning but without any current passing through the
motor. The revolving pinion slides into mesh with
the flywheel teeth, and by the time the gears are fully
meshed, the contact piece in the swit^ has come
against the main contacts Q, thus closing the circuit
between the battery and motor without the resistance,
so that the. full battery voltage is used for cranking.
As in the last case considered, an overrunning clutch
is carried in the starting motor housing or in one
of the intermediate gears.
Another method somewhat similar to those just
described is found in equipments that apply a small
amount of power to the motor armature so that the
pinion is kept revolving until the gears are in mesh.
An example of this method is found in Delco motor-
dynamos, whose armatures and fields each have two
windings, one for generating and the other for starting.
When the ignition switch is closed, the battery current
is sent through the dynamo fields and armature wind-
ings so that the armature and the small starting pin-
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200 STARTING AND LIGHTING
ion is caused to revolve slowly and with very little
power. As soon as the gears have been meshed, the
full battery voltage is applied for cranking.
While most of the double-reduction gear applica-
tions described operate with an overrunning clutch
between starting motor and crankshaft or flywheel,
this unit is not absolutely necessary. A number of
applications of Bijur systems have been made in
which the sliding pinion is carried on the extension
of. the armature shaft and meshes with* the flywheel
teeth without the use of a clutch. In this case it is
very essential that the starting switch be released as
soon as the engine starts to flre, as otherwise the
motor armature will be driven at dangerously high
speeds.
STARTING SWITCHES
A majority of starting switches now in use may be
divided into two classes, ^ne of which (Figure 89)
provides only a single pair of contacts that allow
the full battery voltage to be impressed on the start-
ing motor when the switch is closed, and the other one
of which (Figure 90) uses two pairs of contacts in
such a way that the battery and starting motor cir-
cuit is flrst completed through a resistance and then,
with further movement of the switch, this resistance
is cut out and the full battery voltage and current is
used for cranking. The forms that these two types
may take are many, and will vary with the make of
equipment and with the model in almost all cases.
Their construction is quite simple, both electrically
and mechanically, and may be easily understood from
a superficial examination. The contact points and
the contact arms are built large and heavy so that
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DRIVE METHODS AND STARTING SWITCHES 201
they are able to carry heavy amperage without undue
resistance or heating. The starting switch terminals
are oftentimes used for the attachment of lines used
for the lighting and charging circuits, so that the
wiring leading to and from the starting switch may
apparently be complicated because of this use of its
terminals for junction points.
A single pair of contacts will always be used with
systems having a Bendix screw or inertia pinion for
starting drive. "The single contact switch may also
be used with many of the systems having an over-
running clutch. A double contact switch is used
when it is desired to start the pinion in motion before
meshing takes place, and will be used when no over-
running clutch is provided.
Magnetic Switches. — Several Westinghouse systems
have made use of a starting switch that is operated
by an electromagnet, the electromagnet being ener-
gized when the driver presses a button conveniently
located at sotne point within his reach. The connec-
tions for such a switch are shown in Figure 91, and
the operation is as follows: When the pushbutton
is pressed, current flows from the grounded side of
the battery to the button, through the button and to
the electromagnet winding in the starting switch.
From the magnet in the switch the current passes to
the dynamo, then back through a connection made in
the switch housing, and to the other side of the bat-
tery. The pull of this electromagnet in the switch
attracts the armature of the magnet, and this armature
carries the contact piece for the main switch contacts.
With the main contacts closed, the current flows
through the switch and to the starting motor. In
series with the starting motor circuit is a solenoid
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202
STARTING AND LIGHTING
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DRIVE METHODS AND STARTING SWITCHES 208
through whose windings passes the core attached to
the gear meshing rod, and the gears are brought into
mesh by the action of this solenoid. The starting
button causes the switch magnet to become energized,
and the flow thus allowed to pass through the switch
energizes the solenoid so that the gears are meshed.
As soon as the engine starts to run, it drives the
dynamo, and the current from the dynamo that passes
to the battery flows in a direction opposite to that
allowed by closing the starting button with the dy-
namo idle. Because of this reversal of current, the
electromagnet in the switch is demagnetized just as
soon as the cut-out doses, and the starting switch
contacts are immediately opened. No amount of
pressing on the start button can cause the starting
switch to close and the gears to meefh with the engine
running for the reason that the current for this
operation cannot pass to the electro magnets while
the cut-out is closed.
Motor Brush Switches, — ^A movement of the start-
ing motor brushes, either one or both of them, has
been used with many of the Delco systems, and with
some others, to take the place of a switch. By this
method (Figure 92), the starting motor brush arm
is pivoted so that the brush may be drawn away from
the commutator surface or allowed to rest on it. With
the engine idle the brush is held away from the
commutator by linkage from, the starting pedal con-
nections. With the usual construction an extension
on the starting brush-arm is used to complete the con-
nection between the dynamo brushes and the battery
circuits. When the ignition button is closed, or when
the electromagnetic cut-out contacts are closed by
mechanical connections from the starting pedal, the
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204
STARTING AND LIGHTING
battery current flows through the dynamo armature
and fields and causes the armature and starting pinion
to revolve so that gear meshing can take place. When
the starting pedal and its connections have moved
MOTOR
BRUSH
SWITCH
Figure 92. — Starting Switch Action with Movable Brush (Delco).
into such a position that the gears are in full mesh,
the connections in the motor-dynamo housing allow
the movable starting motor brush to drop onto its
commutator, thus completing the battery circuit
through the starting coils on the armature and
through the series field windings. When the starting
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DRIVE METHODS AND STARTING SWITCHES 205
brush drops onto its commutator, the movement of
the brush-arm causes the connection from the dynamo
brushes to the battery to be broken so that during the
cranking operation no current can flow to or from
the dynamo windings. As soon as the engine has
started, the pedal is released and the gears pass out
of mesh at the same time that lifting of the movable
starting brush breaks the starting circuit while re-
establishing the dynamo connection with the battery
lines so that charging can take place.
Motor-Dynamo /Sw^cfe*^.— Motor-dynamos may be
divided into two classes, one of which will include
those machines that complete the connection between
battery and electric unit for starting and then allow
this connection to remain closed while the motor-
dynamo speed becomes high enough to cause battery
charging. (See Figures 59 and 60.) The other class
includes those machines that complete the connection
for starting through one of the usual forms of start-
ing switch and complete the charging connection
through an electromagnetic cut-out. The latter sys-
tem is always used with installations that use a high
starting voltage and a comparatively low charging
and lighting voltage, because it would be manifestly
impracticable to allow a machine that generates a
low voltage to remain connected to the battery with
the battery sections so connected as to produce a high
voltage, as used in starting.
The connections made by switches which establish
a circuit that is maintained for both starting and
charging have been described in Chapter V under
, * 'Cut-Outs." Practically any of the types making a
single contact for starting may be used with dual
voltage equipments.
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206 STARTING AND LIGHTING
Commutating Smtches. — The type of switch used
with motor-dynamos that use a starting voltage higher
than the charging voltage is known as a commutating
switch, because it changes the connections between
the battery and the electric machine to allow for either
of the functions to take place. With' such switches
in the idle or running position, the sections of the
battery are connected in parallel or multiple, so that
the voltage of the whole battery will be no greater
than one section and will be correct for lighting and
charging. With the switch in the starting position,
the battery sections will be connected in series with
each other, and the voltage of the whole battery will
be equal to the voltage of one section multiplied by
the number of sections used.
The connections made by the switch used with
Splitdorf-Apelco systems, having twelve-volt starting
and six-volt lighting and charging, are shown in Fig-
ure 93. The two positive terminals of the battery
are connected to the switch terminals marked -{-A
and +B, while the negative terminals of the battery
sections are connected to terminals — A and — B-D.
Eight contact points are carried inside of the switch,
four of which are connected, two and two, in the run-
ning position, while the remaining four are likewise
connected, two and two, during cranking. With the
contact members in the running position, the flow of
current is as follows : From the positive terminal of
the motor-dynamo, as a dynamo, through the cut-out
and to the starting switch terminal marked -{-A, by
means of the wire 12. From this terminal the current
flows through one line directly to one of the positive
terminals on the battery and also through the internal
connections of the switch and through the contact
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DRIVE METHODS AND STARTING SWITCHES
207
member to the switch terminal +J5 and to the positive
terminal of the other battery section. Prom the
Figure 93.— Connections for Commntating Starting Switch (Spllt-
dorf-Apelco).
— B'D switch terminal, which carries the Jine from
one of the negative terminals of the battery, another
line runs directly to the negative dynamo terminal of
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208 STARTING AND LIGHTING
the motor-dynamo, while the connection from the
switch terminal — A and the other negative terminal
of the battery comes through the internal connections
of the switch and the other contact member to the
switch terminal — B-D,. where it joins the current
from the othei: battery section in its path to the dy-
namo. It will thus be seen that both sections of the
battery are connected with the dynamo, with both
positives together on one side and both negatives on
the other side of the starting switch.
With the switch contact members in the starting
position, the flow of current is as follows:. From
one of the positive terminals on the battery to switch
terminal -\-A, then through the switch contact piece
to terminal +-3f , and to the starting motor terminal
on the motor-dynamo. Passing through the starting
motor fields and armature of the motor-dynamo, the
current returns to switch terminal — B-D, and to one
of the negative terminals on the battery through the
other line attaching to this same switch terminal.
Passing through this section of the battery, the cur-
rent flows to switph terminal -\-B, through the switch
contact member and to terminal — A, thence back to
the negative terminal of the battery section from
whose positive terminal the tracing of the flow com-
menced. It will thus be seen that the flow is through
each section of the battery, first one and then the
other, also through the starting motor, so that both
sections of the battery and the starting motor are in
one series circuit.
The connections made by the Simms-Huflf c6mmn-
tating switch are shown in Figure 94. The sliding
contacts move from right to left in the position illus-
trated, and are drawn in full lines for the running
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DRIVE METHODS AND STARTING SWITCHES
200
and charging position and in dotted lines for the
starting position. In the charging position one of
the positive terminals of the battery connects with
switch termilial i, and through the wire A to terminal
4. The other positive terminal of the battery con-
nects with switch terminal 5, and through the sliding
contact piece with terminal 4. Both sides of the bat-
tery are thus joined at 4, and from this terminal a
' line leads through the cut-out (not shown) to the posi-
fi*igure 94. — Commutating Starting Switch with Sliding Contacts
(Simms-Huff).
tive terminal on the motor-dynamo. The negative side
of the motor-dynamo is grounded, and one of the neg-
ative terminals of the battery is also grounded di-
rectly. The other negative terminal of the battery is
attached to switch terminal 2, and by means of the
sliding contact piece to terminal 3, which is grounded.
Both battery negatives are, therefore, connected to-
gether, and both positives are likewise connected.
The positives are connected to the positive side of the
djmamo and the negatives are connected with the
negative side of the dynamo through the ground con-
nections.
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210 STARTING AND LIGHTING
With the switch contacts in the starting positions,
the current flow starts from the positive terminal of -
the battery section marked B and passes to the switch
terminal 1. Then through the contact "piece in the
switch to terminal 2, and back to the negative side of
battery section L. After flowing through section L,
the current passes to switch terminal 5 from the
positive side of the battery section, and through the
contact piece in the switch to the starting motor ter-
minal on the motor-dynamo. Passing through the
motor, the current flows to ground and through the
metal of the car returns to the grounded negative
terminal of battery section B, having completed a
series circuit through both battery sections and the
motor-dynamo.
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CHAPTER VII
INDICATING DEVICES AND TROUBLE LOCATION
Because of the fact that almost any trouble that
may come to the electrical equipment will cause some
change in current flow or pressure, the subject of
indicating instruments is closely allied with that of
trouble location. As mentioned in Chapter I, there
are six divisions into which most all of these instru-
ments may be divided, these divisions being the am-
meter, the voltmeter, combined voltammeters, current
indicators, moving targets, and pilot lamps.
Ammeters. — ^Ammeters may be built upon any one
of a number of different principles, and they may be
built cheaply or made very expensive. Regardless
of the type or quality of the instrument, the flow of
curt*ent which conforms to the definition of one am-
pere remains the same, and because of this fact the
various constructions will not be treated at length.
As a general rule, the construction of an ammeter
and a voltmeter does not differ materially according
to whether the instrument is to measure amperes or
volts. In the case of the ammeter, the flow is allowed
to contiQue without appreciable resistance, and it is
this flow of current that is measured. With the volt-
meter the flow is practically stopped because of the
very high resistance of the instrument, and this stop-
page allows the pressure that is acting in the circuit
to be measured. Even in the case of the voltmeter
(for all types in general use) there is some passage
211
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212 STARTING AND LIGHTING
of current, and the construction and principles of
action are the same as for the ammeter, the sole dif- .
ference being in the amount of flow allowed to pass
throifgh the instrument.
Ammeters are provided with a pointer or hand
which moves from side to side with increase or decrease
of flow through the circuit in which the instrument is
placed. The pointer moves across a scale graduated
in amperes or fractions and multiples of amperes and
having a zero point at or near the center of the gradu-
Figure 95. — ^Zero Center Ammeter.
ations. The pointer will move one way from this zero
point with flow of current in one direction, for in-
stance, into the battery, and will move in the opposite
direction from the zero point when current flows in
the opposite direction, as would be the case during
battery discharge. This type of instrument is known
as a **zero center" ammeter (Figure 95). If the
meter was built in such a way that the hand stood at
one side of the scale when at zero, it would only
measure the flow of current in one direction, and
would not be suitable for attachment on the car.
Ammeter scales may be marked ** Charge" on one
side and ** Discharge" on the other side of zero, and
when marked they should be so connected to the bat-
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INDICATING DEVICES AND TROUBLE LOCATION 213
tery circuits that the hand will swing to ** Discharge'*
when current is flowing out of the battery, such as'
would be the case with lamps turned on and the
engine standing idle. The hand will then swing to
** Charge" when current is flowing from, the dynamo
into the battery.
An ammeter should be placed on a car and so con-,
nected that it will measure all of the current flowing
into the battery from the dynamo, and so that it will
measure all current leaving the battery except that
used for starting. An ammeter sufficiently great. in
capacity to measure the large flow during the crank-
ing operation would have a scale too coarsely divided
to measure the small currents used for charging and
lighting. It is, therefore, necessary to flnd a wire on
the car that carries all of the charging current and
all of the lighting and other accessories' current, but
none of 'the starting current. This may usually be
done by following either one of the large battery
cables until a smaller line branches from this cable.
The ammeter may then be attached in this smaller
line and just as close to the4arge cable as possible.
Provided the wire selected carries all of the lighting
and chai^ng current and none of the starting cur-
rent, the ammeter will then indicate the net charge
and discharge other than for starting.
Should the charging wires and the lighting wires
be connected to the large cables from the battery at
different points along these heavy cables, it will not
be possible to attach an ammeter to show both charge
and discharge. This will also be the case with a
great many motor-dynamo systems in which no line
can be selected that carries both charging and light-
ing currents that does not also carry the starting am-
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214 STARTING AND LIGHTING
perage. It will often be found possible to attach an
ammeter so that it will show charge into the battery,
but no discharge for the lamps and other current-
consuming devices. It will also be possible to attach
an ammeter to one side of a separate dynamo so that
the dynamo output will be indicated, this method,
however, being of comparatively little value because
it is the current entering the battery that is more
essential than that furnished by the dynamo. In
the absence, of special directions for attaching an
ammeter it will be necessary to follow the wiring as
described or else to examine a wiring diagram of
the car or system in question until a line is found
that does not carry the starting current but that does
carry the currents whose value it is desired to
measure.
With an ammeter connected, some lamps should be
turned on and the direction in which the needle moves
noted. If the scale is marked ** Chaise'' and **Di».
charge, ' ' the needle should move toward * * Discharge, ' '
and if it does not do so, the wires should be removed
from the ammeter terminals and interchanged with
each other. In case the face of the meter is not
marked, the connections should be made in such a
way that the needle will swing to the right of zero for
charge and to the left for discharge.
Voltmeters.— A voltmeter may be attached between
any two points or any two wires whose difference in
pressure or voltage it is desired to measure. While
an ammeter should always be placed in series with
the circuit whose flow it is to measure, the voltmeter
is very seldom placed in series for the simple reason
that its resistance is so high that practically no cur-
rent flow could take place with the instrument so
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INDICATING DEVICES AND TROUBLE LOCATION 215
connected. In connecting a(n ammeter, the circuit is
broken at some point and one side of the meter con-
nected to one end of the circuit, while the other side
of the meter is attached to the other end of the cir-
cuit. No such procedure is necessary with a volt-
meter, it being only necessary to place the wires from
the voltmeter on the points whose voltage is to be
measured, and the needle of the instrument then
shows the voltage difference existing at that time.
When voltmeters are mounted as part of the equip-
ment of a car, they are attached to the positive and
Figure 96. — ^Voltmeter and Ammeter Connections.
A — ^Ammeter. B — Voltmeter.
negative side of the circuit between battery and dy-
namo, and usually oh the djmamo side of the cut-out
(Figure 96), A voltmeter draws such a very small
flow of current that the loss from this use may be
neglected while the engine is running. However, it
would not be advisable to connect a voltmeter directly
,to the terminals of a battery and allow it to remain,
there, because even such a slight flow of current con-
tinued without any interruption would eventually
discharge the battery wholly or partially. To attach
a voltmeter correctly, the car's wiring should be exam-
ined and the line from the dynamo to the cut-out
found. One side of the voltmeter should then be
attached to this line, either at the dynamo or cut-out
pr any other convenient point. The oth^r side of the
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216 STARTING AND LIGHTING
voltmeter may then be attached to any other wire or
terminal between battery and djmamo, provided that
this second point of connection is of opposite polarity
from the first. The meter will then indicate the
charging voltage at all times while the engine is run-
ning fast enough to close the cut-out.
Voltmeters are sometimes attached directly to the
battery so that they indicate the battery voltage or
the voltage at the battery terminals at all times.
Such a connection should not be made unless the
meter is known to be of a type designed for such use,
and should then be used in accordance with instruc-
tions given by the makers of the car or of the elec-
trical equipment.
Voltammeters. — ^Because of the similarity between
the voltmeter and the ammeter, it is quite possible
to use a single instrument for both purposes. The
voltammeter consists of a single movement which is
fitted with suitable terminals and resistances to allow
its use in either capacity. Voltammeters are usually
provided with One terminal for use in voltage measure-
ments, with one terminal for use in measuring am-
perage, and with one terminal for use with either one
of the two first mentioned, regardless of whether volts
or amperes are being measured. A voltammeter may
be provided with a switch which is turned to take
voltage readings, or may simply require that the con-
nection be made on the voltmeter terminal. While
such combinations are in common use as portable
testing instruments, they are seldom found attached
to the automobile as a permanent part of the elebtrical
equipment.
Indicators. — These instruments have faces or dials
showing three conditions — ''Charge," ''Off," and
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INDICATING DEVICES AND TROUBLE LOCATION 217
''Discharge" — the **Oflf" position corresponding to
zero on the ammeter. They are constructed on the
principles employed in the ammeter, 4>ut do not meas-
ure the exact amperage. They may be so constructed
that attachment in the main batt^^ circuit is possible
and so that all charging current and all discharge,
including that for starting, passes through them.
With the engine running fast enough to cause charg-
ing, and with the lamps and other current-consuming
devices out of use, an indicator should show
** Charge." "With any current being drawn from the
Figure 97. — "Charge-Off-Discharge" Indicator.
battery the instrument should show ** Discharge."
(See Figure 97.)
Targets. — Because of the fact that some part of
the electromagnetic cut-out must move when the con-
nection between dynamo and battery is completed,
it is possible to use some visible marker or target
attached to the cut-out as a current indicating device.
It should be understood that because the cut-out is
closed it does not necessarily mean that the battery
is being charged. The lamps turned on at that time
may be consuming all of the current generated, or
the cut-out itself may be defective and not completing
the circuit to the battery, although apparently do-
ing so.
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218 STARTING AND LIGHTING
PUot Lamps. — Dash lamps connected in such a way
that they light up when the cut-out closes are used
with some installations. The same caution applies
in a certain measure as given for the target, that is,
that this type of indicator does not necessarily prove
that the battery is being charged. A pilot lamp con-
nected between djmamo and battery is a fairly reli-
able indication, however, and because of the propor-
tion of charging current that passes through it, the
lamp should never be allowed to remain out of its
socket or burned out.
It should be borne in mind that ail types of current-
measuring and indicating devices are subject to
troubles that render their indications of little or no
value. Ammeters and voltmeters should be watched
to make sure that they indicate zero when the engine
is. idle and all lamps out. If there is an error either
way, this error should be allowed for in making read-
ings with the instrument. It may happen, and often
does happen, that the magnet used in these instru-
ments becomes damaged or too weak to perform its
work, and in this case the meter will become very
sluggish and its hand will tend to stay in whatever
position it comes to rest until the current flow is high
in value. "While the higher-priced instruments have
provision for resetting the hand or dial at zero, the
low-priced voltmeters and ammeters are valueless
when damaged, and it is economy to replace them
with new ones.
STARTING AND LIGHTING TROUBLES
Faulty operation of the various units may appear
in one of two forms, either electrical trouble or
mechanical trouble. Mechanical troubles include
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INDICATING DEVICES AND TROUBLE LOCATION 219
those caused by loose, broken and worn parts, by
incorrect assembling and lack of proper care and up-
keep, such as lubrication and cleaning. Electrical
troubles include the faults that prevent the current
from traveling in its proper paths and from doing
the work that is expected of it. Almost all electrical
troubles may be placed under one of four headings,
namely:. (1) open circuits, (2) circuits having ab-
normally high resistance, (3) short circuits, and (4)
y^" ^ i Ij I '
D
s
Figure 98. — Troubles in Wiring System.
G — ^Accidental Ground.
O — Open Circuit.
R^— High Resistance.
S — Short Circuit.
the modification of short circtdt called a * Aground.'*
(See Figure 98.)
An open ijircuit occurs whenever a wire breaks or
becomes detached from one of its terminal connections
so that the current can no longer flow. An open
circuit may also be caused by an improperly made or
dirty connection in which the current-carrying sur-
faces do not make proper contact with each other.
Any fault that prevents the current from flowing
because of the lack of a complete path op circuit away
from and back to the battery is said to result in an
open circuit, or simply an **open.**
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220 STARTING AND L.lGnTING
High resistance may result from poorly made or
dirty contacts in which the current-carrying sur-
faces are in partial contact. The area of the con-
ductors is so reduced in size that all but a small
amount of current is prevented from passing the
point of high resistance. Wires that are partially
broken through and wires that are too small for the
work they must do will cause an abnormally high
resistance. Dirty, pitted or corroded contacts in the
dynamo, cut-out or regulating parts will cause high
resistance, and, in fact, any fault ihat results in a
partial stoppage of current flow through a circuit
that should be complete and of low resistance will
bring this trouble about.
A short circuit is established whenever an acci-
dental current-carrying path occurs in a circuit at a
point that allows a flow from the battery when there
should be no flow, or that allows the current to leave
the battery and return to it without passing through
the lamps or other devices that are designed for cur-
rent consumption. The success of any electrical
installation depends on the flow of current being kept
within the conductors designed to carry it, and should
the insulation fail or should exposed parts come into
contact in such a way that an improper flow is
allowed, the result will be a drain on the battery,
failure of the dynamo to generate, failure of the start-
ing motor to act, or a failure of almost any of the
electrical units, depending on the point at which the
short-circuit occurs. -
A ground is a form of short-circuit that is estab- '
lished through the metal work of the car. With the
one-wire system, or the grounded return system, an
accidental ground will occur whenever a current-
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INDICATING DBVICHS AND TROUBLE LOCATION 221
carrying conductor comes into electrical contact with
a part of the metal of the car. With a two-wire, or
insulated return system, it is necessary that both
sides of the circuit come into electrical contact with
the metal of the car. This fault is rarely met with
in the two-wire system because of the fact that the
metal work of the car does not ordinarily act as a
conductor for one side of the circuit
Indicating Instrument Fa/ults. — Because of the fact
that ammeters, voltmeters, etc., are primarily designed
to tell what is happening and to aid in locating
trouble, it shomld not be assumed that these units
themselves are free from error. Outside of trouble
caused by open, short or grounded circuits and cir-
cuits of high resistance in the wiring and terminal
connections of these instruments, they may develop
trouble within their mechanism. Should an ammeter
be subjected to a current much greater than it is
designed to carry, such as would be the case were an
ordinary instrument connected in the starting cir-
cuit, the current-carrying coils would be burned out
and the meter would have to be rebuilt before further
use could be made of it. An ammeter or voltmeter
of the permanent magnet type, such as is ordinarily
employed, will lose its accuracy if exposed to heat,
sudden jars or a strong magnetic field. The first
and most apparent effect of such a happening will
be a sluggish action of the indicating hand. The
hand will move slowly from place to place on the dial,
and will not return to zero until jarred, if at all. It
is quite frequently found that a meter hand does not
return to the zero point when cuYrent flow or pressure
is removed, yet the action may be satisfactory in all
other ways. To overcome this diflSculty, to which all
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222 STARTING AND LIGHTING
meters are more or less subject, high-grade instru-
ments are provided with a **zero center*' adjustment
by which the tension of the springs controlling the
movement may be changed or by which the dial itself
may be moved until the position is again correct.
When an ammeter or voltmeter is in proper working
order, the hand should remain at zero with one or
both of the wires removed from its terminals. Should
there be an error at this time, the number of amperes
or volts should be noted and allowed for in future
readings. The hand should move quickly from point
to point and should come to rest within a reasonable
time.
Should an indicating target such as is attached to
an electromagnetic cut-out fail to indicate charge
with the engine running at a fair rate of speed,
trouble in the cut-out is indicated, or else a failure
in the dynamo or other parts of the charging system
that prevents the cut-out from closing. Failure of
a pilot lamp to light indicates that the lamp bulb is
broken or burned out or else that one of the cut-out
troubles mentioned above is present.
LIGHTING SYSTEOi TROUBLES
The lighting system of the car consists of the
lamps, together with the necessary wiring, switches,
fuses, circuit breakers and junction connections.
Lighting trouble that is not a result of lack of charge
or voltage at the battery will be found in one or more
of the above mentioned units.
In case of failure to light, the bulbs themselves
should be examined to make sure that they are not
broken and that the filaments are not burned out.
Should the lamp have been fitted with bulbs designed
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INDICATING DEVICES AND TROUBLE LOCATION 223
for a voltage lower than that used on the ear, the fila-
ments will be burned out, while bulbs designed for a
higher voltage than that used will not light at all.
The average life of a good tungsten filament bulb,
should be from 100 to 300 hours, but low-efficiency
or cheap bulbs may become dim or may bum out in
much less time.
It is quite possible for dirt, loose wire strands or
faulty construction to cause an accidental short-circuit
in the bulb base or in the socket into which the base
fits. Such a fault will probably result in allowing
such a heavy flow of current at the defective point
that heating will result, and at the same time all the
other lamps on that circuit or line wUl burn dimly
or not at all. It may be found that the small contact
points on the bottom of the bulb base do not make
contact with the plungers or springs in the socket.
The springs may be bent up slightly or the contact
points may be extended by the addition of a drop of
solder to each. If the socket contains spring plungers,
they should be pressed down and examined for bind-
ing or dirt that will cause sticking, when the bulb
base is pressed home. If the plungers can be pressed
down and then remain down, it indicates that the
springs have become broken or are binding, and a
new socket is the most satisfactory remedy. The
interior of the bulb sockets should be kept free from
dirt and foreign matter of all kinds because the result
may be either a short-circuit or an open circuit for
that particular lamp. It is customary to provide
the lamps with connectors into which the wires fasten
and which complete the circuit by means of plungers
or pins that fit into holes in a se<3ond part of the
connector. The same remarks respecting dirt and
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224 STARTING AND LIGHTING
poor connections apply to these outside connectors as
to the bulb sockets. Should the lamps flicker and
occasionally go out altogether, the wiring at the sock-
ets and at the connectors should be examined for loose
strands. In case a part of the copper is found exposed,
it should be wrapped with insulating tape to prevent
a repetition of the trouble caused by the movement
and jarring of the car while in motion.
Should trouble manifest itself in one or more lamp
groups and no faults be found with the lamps or
bulbs, the wiring for the affected portion of the eq^uip-
ment should be carefully examined to locate possible
short, open or grounded circuits. The insulation
should be perfect along the entire length of each,
wire, and any worn places should be well wrapped
with tape. The points at which the wires turn around
comers, and the points of fastening by means of
cleats on the metal work, should be given a careful
inspection, and the conductors should be moved wher-
ever possible while the lamp switches are turned on
to test for broken wires underneath the insulation.
In case the candlepower of the lamps has been in-
creased, or in case additional lamps or other acces-
sories have been added to any of the circuits, it is
quite possible, that the wire originally used may be
too small for the added load. Lamp circuits should
be made with wire not smaller than No. 14 gauge, and
12 gauge will be safer in case of any added load.
Wires of opposite polarity should not be run so close
together that they touch unless they are bouild to-
gether with tape or fasteners, because of the chafing
that will result. In case it is necessary to run lines
through places where they will become wet or oily,
thfi wiring should be enclosed in metal conduits or by
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INDICATING DEVICES AND TROUBLE LOCATION 225
circular loom, and the openings through which the
wires enter and leave the protecting coverings should
be tightly taped. . '
A large number of cars are equipped with bus-
bars, junction blocks or boxes and distribution panels
at the terminal posts of which several lines meet and
are connected together (Figure 99). These points of
connection may develop short circuits between the
several cables of different circuits, or may contain
accidental grounds on the metal work of the car.
Loose strands of wire should be carefully guarded
Figure 99.— Distribution Panel.
B — Bus-Bar. J — Junctions.
against, and all such wire ends should be fitted with
metallic terminal pieces that hold all the wire strands
by means of the solder used in making the attach-
ment. It is often found that dirt, oil or moisture
enters these connection boxes through the wire open-
ings, and in case the junctions are located at points
exposed to such trouble, it will be well to tape each
line where it enters the enclosed portion of the junc-
tion.
In the case of a car equipped with fuses in the light-
ing or charging lines, these units should be examined
to make sure that the circuit can be completed from
end. to end. The fuses are designed to protect the
equipment against short circuits and overloads, and
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226 STARTING AND LIGHTING
should a fuse be found burned out, the line leading
away from it should be examined for the short circuit
that is almost sure to be found. It will do no good to
replace a fuse in a lighting circuit until the cause
of its burning out is found and remedied^ because a
new fuse will only suffer in the same way as the old
one as soon as the faulty conditions reappear. Fuses
should never be replaced with others of a higher
capacity than those originally furnished mth the car,
because the protection to the circuits and other units
will no longer be present. The final result of such
replacement will probably be damage many times
more serious and more costly than the new fuse of
the proper size would have been. Such advice applies
even in stronger measure to replacement of fuses with
lengths of copper wire. This is the poorest kind of
economy and should never be practiced. It will
oftentimes be found that a failure to complete a cir-
cuit through a fuse is due to poor contact of the fuse
with its holding clips or due to poor contact of the
clips and terminals with the wire ends that are at-
tached at these points. A minute piece of foreign
matter between the fuse and the clip will prevent a
flow of current, and before deciding that the fuse is
burned out, it should be turned around in the clips
once or twice to remove any such particles. The clip
ends should be pressed together until they hold the
fuse firmly, and the screws that hold the wire ter-
minals should be turned down tight.
The contact points of circuit breakers should give
no trouble because they are so seldom called upon. to
do any work. In case of high resistance or an open
circuit in lin^^s protected by these devices it can do
no harm to examine them and to clean the contacts
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INDICATING DEVICES AND TROUBLE LOCATION 227
by drawing strips of very fine emery cloth between
them while held closed. In case a circuit breaker
opens, it indicates an overload on that line, and this
overload, whether caused by short circuit, ground or
improper connections, should be located before the
breaker is closed. Some types of circuit breakers
will open and close rapidly with a buzzing noise as
long as the trouble is present, and the spring tension
or adjustment should never be changed to overcome
an accidental leakage of current.
Should the lamps flicker or go out entirely, it is
possible that the trouble will be found in the lighting
switches. These switches are simple in construction,
and their action may be understood in each case by
an examination. The contacts- should be examined
to make sure that they close their respective circuits
and to make sure that the leaves are not bent or bind-
ing and that the surfaces are clean and bright. The
moving parts of the switch may have become loose so
that they make only an intermittent connection while
the ear is in motion, and all of the internal parts
should be moved by hand to determine whether this
trouble is present. The terminal studs and nuts
should be watched for looseness or breakage, either
external or internal, and in case of any doubt as to
the proper connections being made, a wiring diagram
for the car being handled should be consulted.
CHARGING SYSTEM TROUBLES
Any failure of the dynamo, cut-out, regulating de-
vice or charging wiring will result in the specific
gravity of the battery electrolyte becoming abnormally
low, and in the voltage of the battery falling below
two for each cell. As far as the wiring is concerned,
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228 STARTING AND LIGHTING
the same advice as that given for the lighting circuits
may be applied to this case. Other troubles may come
from faulty conditions of the dynamo brushes, com-
mutator, armature or fields, or from faults in the
cut-out and regulator.
In case a test at the dynamo with an. ammeter shows
no flow of current, or if a voltmeter test shows no volt-
age being generated, it may be assumed that parts
inside of the dynamo housing are at fault. While
either the cut-out or regulator or both of these units
may be carried inside of or on the dynamo housing,
they are not properly a part of the dynamo, and will
be given separate consideration.
With the brushes exposed, their holders should be
examined to see that the pivoted arms are free to
swing back and forth, and that sliding brushes do
not bind or wedge in any position. Such binding of
the brush itself may be remedied by carefully dress-
ing the sides with a fine file. Attached to each brush
or to the brush holder is a short length of flexible
wire called the brush pigtail. These small wires must
not be broken and their connections must be clean
and tight at each end.
Either the brush itself or else the brush holder is
held by a coiled or flat spring so that the brush bears
on the commutator surface with a tension just suffi-
cient to cause the brush end to make good contact at
all armature speeds. These brush springs should not
be bent, loose, broken or binding, and should have
sufficient tension to cause a good firm connection to
be maintained, but should not be set up so tight that
there is danger of the brush cutting into the commu-
tator surface.
In all types of dynamos the brushes or their holders
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INDICATING DEVICES AND TROUBLE LOCATION 229
are insulated from the remainder of tlie dynamo by
means of bushings, washers and sleeves. These insu-
lating parts must not be broken or cracked, and if
covered with oil or carbon dust should be thoroughly
cleaned. In the case of grounded return systems, the
ground connection is made through the pig-tail, but
the brush itself is insulated.
The end of the brush must exactly fit the curve of
the commutator in those machines that provide brush
contact on the curved outer part of the eomjnutator.
In case the contact surface of the commutator is
formed from the flat side of the ring, the surface of
the brush must then be perfectly flat and bear evenly
at aU points on the segments that pass under it during
armature rotation. The brush end may be fitted to
the commutator by drawing strips of thin fine-grain
sandpaper between brush and commutator with the
sand side toward the brush, this procedure having
been described in the chapter on dynamos and shown
in Figure 21.
The brushes should be replaced with new ones
when worn down nearly to the holder or spring, and
in making such a replacement the safest method is
to secure the new brushes from the makers of the
car or the makers of the electrical equipment. As a
general rule it may be said that none but carbon or
carbon composition brushes should be used, because
of the fact that brushes made from copper or copper
alloys tend to cut into the commutator surface and
cause serious damage and rapid wearing. Even with
carbon brushes in use, care must be exercised to see
that the material is very fine and of smooth grain.
Brushes that are light gray in color and that show a
granular or rough surface are not safe to use.
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230 STARTING AND LIGHTING
Should the bru&hes be found in good condition,
the commutator should be examined next. Its surface
should be very smooth and should preferably have a
glazed appearance and a dark brown color. In case
the surface of the segments is found to be dirty,
scratched, rough or pitted it may be dressed with
fine sandpaper by following the method described in
the chapter on dynamos. Excessive sparking will
cause burning and pitting of the commutator sur-
face, and this sparking will usually be found to result
from the use of brushes of improper material or from
the fact that the brushes do not make good contact
with the commutatcfr.
The segments forming the commutator should be
examined to see that none of them are projecting
above the surrounding surfaces and that all are up
even with the curve of the commutator. These
troubles may be corrected by turning the commutator
in a lathe, but if the condition is the resist of loose
segments or fastenings, the armature should be sent
to its makers for repairs. The small wires that con-
nect the segments with the armature coils should be
watched to see that they are unbroken and well insu-
lated. Worn or broken insulation may be replaced by
taping and then shellacing over the surface of the
tape. If the connecting wires are broken they should
be fastened in place with hard solder or silver solder.
The insulation between the segments should be
below the surface of the commutator, and if found
even with or above the surface of the surrounding
segments, it should be dressed with some cutting tool
such as described in the method given in Chapter II.
Armature and Field Testing. — In order to handle
this class of work it will be well to secure a circuit
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INDICATING DEVICES AND TROUBLE LOCATION 231
tester of some f onn which will indicate by a flow of
current when a circuit is complete through a certain
path and when it is incomplete. A very satisfactory
tester may be made by cutting one side or one wire
of an ordinary drop-cord such as is used for shop
and garage lighting. See Figure 100. Cutting one
wire in this way will cause the lamp to go out, even
though the switch be turned on, but as soon as the
two ends of the severed wire are brought together,
the circuit will be completed and the lamp will indi-
(^^|S=
Figure 100.— Circuit Tester.
cate this fact by lighting. These two free ends of
one side of the circuit may be used as a tester by
touching them to any two points between which it is
desired to make a test. For example, with the wire
ends touched to the two ends of a conductor that is
completing its circuit, the lamp will light because the
circuit is now made through the conductor being
tested. If the conducting path is not complete, the
lamp will indicate this fact by remaining dark. In
case it is desired to know whether or not a certain
wire is grounded, one of the test wires may be touched
to the metal of the car and the other test wire to the
wire being tested. Should the lamp light, it indi-
cates that the wire being tested is in electrical con-
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232
STARTING AND LIGHTING
nection with the metal of the ear and is therefore
grounded.
The troubles most commonly found with armatures
are burned out or broken windings and windings
grounded to the core or armature shaft. With one
end of the test wire touching any point on the sur-
face of the commutator, the lamp should light when
the other test wire is touched to any other point on
the commutator. Should the lamp remain out with
the connection made at any point, it indicates that
the winding connected to the segment being touched
>|
MMAruRE.
"
J
Figure 101. — Test for Accidental Ground.
is broken or that the segment of the commutator is
disconnected from the armature windings. With one
of the test wires attached to the metal of the arma-
ture shaft or armature coil the lamp should not light
when the other end of the tester is touched to the
commutator at any point on its surface. See Figure
101. Should the lamp light, it indicates that either
the armature windings or the cotiimutator segments
are grounded. To remedy either of these conditions
requires special equipment and experience and the
work should be done by a shop able to handle it
properly.
In order to test the field windings for possible
troubles it will be necessary to reach the terminals
or connections that carry the leads for these windings.
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INDICATING DEVICES AND TROUBLE LOCATION 233
In the case of straight shunt wound dynamos having
an external regulator, one end of the field winding
will attach to one of the dynamo terminals, while the
other end of the winding will lead either to another
dynamo terminal, to a ground connection or directly
to one of the main brushes. In third-brush dynamos
one end of the field winding attaches to the regulating
brush and the other end to one of the main brushes
or to a second field brush. In either of the above
cases, lifting one or more of the brushes away from
the surface of the commutator will usually serve to
Figure 102. — ^Test for Open Circuit.
isolate at least one end of the field coils. The con-
nections for compound wound dynamos, for dynamos
with bucking coils or reversed series field windings
and for motor-dynamos will vary according to the
construction of the machine, and can best be found
by examination and test or by consulting a wiring
diagram that shows the internal connections.
Troubles that occur in the fields may take the form
of burned out or broken windings or connections, of
disconnected terminal fastenings, or of ground con-
nections made with the core or dynamo frame. It
should be possible to secure a connection from one
end of the field windings through to the other end
with the drop-cord circuit tester and the lamp
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234 STARTING AND LIGHTING
should light. Failure to secure such a connection
indicates a broken or disconnected field circuit. With
one of the test wires attached to the metal of the
dynamo, the lamp should not light when the other
end of the test wire is touched to either end of the
field coil while the coil is disconnected from aU other
circuits and from the brushes and commutator. It
should be noted that no circuit test, either to find
whether a circuit is complete or grounded, is of any
value unless the lines to be tested can be separated
from all other connections during the test. Should
any outside wirii^g be left connected, the circuit may-
be completed through another path than the one
being tested and erroneous conclusions will be drawn
in many cases.
The permanent field magnets used on some dynamos
are subject to certain peculiar faults that will not
occur with wound fields. These magnets will grad-
ually become weaker and weaker with long continued
use until they must be removed and remagnetized
just as would the magnets of a magneto used for
ignition. Permanent magnets must not be hammered
or jarred violently, and at all times, 'while removed
from the dynamo, the opposite poles should be joined
with a small bar of iron or steel so that the path of
the magnetic lines of force may be completed through
this so-called ** keeper." Should all of the magnets
.composing the set used on a dynamo be put on the
machine with their poles placed in positions opposite
to that originally occupied, the polarity of the ma-
chine will be reversed and serious damage to the bat-
tery will result if they are not changed immediately.
Should part of the magnets be replaced in the correcft
position, but the remainder be reversed in position,
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INDICATING DEVICES AND TROUBLE LOCATION 236
the several members will oppose each other in action
and the dynamo output will be greatly reduced if not
prevented altogether. It is not good practice to
mount permanent magnet machines on bases made
from iron or steel because the lines of force from the
magnet ends will pass to a great extent through the
metal of the base rather than through the core of the
armature, and the dynamo output will be reduced in
proportion to the loss taking place.
Cut-out Care. — ^Manual or hand-operated cut-outs
require the same care and attention as called for by
any other type of switch. Electromagnetic cut-outs
Figure 103. — Cleaning Contacts.
are of more complicated construction and are subject
to a different class of faults.
The contact points of an electromagnetic cut-out
should be kept clean and bright and should meet
evenly and over their entire surface when the cut-out
is closed. Should plain surface contacts be found
dirty or pitted, they may be cleaned by drawing strips
of thin emery cloth between them while holding them
lightly together. See Figure 103. This method of
using the emery cloth will also restore the surfaces
to such a form that they make full contact in case
they have become out of line for any reason.
When the engine runs at a charging speed, the cut-
out contacts should be closed by the action of the
magnet, provided the dynamo is giving the necessary
voltage. Failure of the cut-out to close when the
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236 STARTING AND LIGHTING
dynamo is in good condition will usually be caused
by loose or dirty connections of the wires on the
cut-out terminals or possibly from a broken or burned
out shunt winding in the cut-out magnet. If the
cut-out closes, but does not complete the circuit for
charging, the contacts should be examined and the
terminal connections of the wires should be made
clean and tight.
Regulation Trovile.r-'THie characteristics and con-
struction of the various systiems of output regulation
will be found described under their several headings
in Chapter V. Their care will be described here in
the same order and under the same names as used
in the former description.
The reversed series field winding is not subject to
any troubles that are peculiar to its regulating func-
tions provided it has been properly designed and
installed when the dynamo was built. This field
winding is, however, subject to the same troubles that
may be encountered with any shunt or series field
and methods of locating such troubles have already
been given.
The third-brush system adds nothing to tne dynamo
for regulating purposes except one or two additional
brushes. These brushes require the same careful fit-
ting that would be called for with any other current-
carrying brushes and the field winding itself does not
differ in any important particular from other shunt
windings and may therefore be handled in the same
way; The same remarks apply to those dynamos hav-
ing compound field windings, inasmuch as in this case
the entire regulating system is found in the series
winding on the field cores.
The iron wire ballast coil of the Rushmore system
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INDICATING DEVICES AND TROUBLE LOCATION 237
of control must be securely held in place by its clips,
just as would be the case for a fuse similarly carried.
See Figure 104. The output is affected by the size
of wire used and information necessary in making
any changes called for has been given in Chapter V.
The coil should be tested in case of trouble to make
sure that the iron 'wire has not become disconnected
and has not been burned out or broken. These trou-
bles will cause the bucking coil to act at all times
with a resulting drop in djoiamo output.
Any form of magnetically controlled field resist-
ance operating on the vibrating principle requires
Figure 104. — Ballast Coil for Rushmore Iron Wire Regulation.
that the regulator contacts and terminal connections
be given the same care as outlined for the electro-
magnetic cut-out. The contacts, when dirty, may be
dressed by using very fine emery cloth drawn be-
tween them, and in this connection it should be noted
that improper wiring of the controller may result in
sending the charging current through the regulator
contacts, which will result in rapid pitting and burn-
ing of the surfaces.
The systems that make use of carbon discs for field
resistance require that the carbon pieces be cleaned
occasionally by removing them from their holders
and rubbing lightly on fairly rough paper. The end
plates of the carbon piles should be cleaned with fine
sandpaper.
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238 STARTING AND LIGHTING
The rheostats found with the Adlake and Vesta
systems of control require cleaning of the contact seg-
ments at certain intervals. This cleaning may be
accomplished by first wiping the surfaces with a
cloth moistened in gasoline and then, should pitting
appear, fine sandpaper may be used to remove the
marks. The brushes should make good contact with
the segments and their surfaces should be kept clean
and smooth. The spring that holds the brush iij
place should have sufficient tension to ensure a good
Figure 105. — Dial of Ampere-Hour Meter (Delco).
current-carrying contact at all times, but should not
bind the contact arm. The plunger of the Adlake
controller should move freely within its socket ai^d
may be cleaned with*a gasoline moiBtened cloth in
case of sluggish action.
All forms of friction clutch governors operated
by centrifugally controlled weights should have the
contact surfaces of their clutches kept clean and free
from dirt or oil. These surfaces may be cleaned with
gasoline and a stiff brush. The weights should be
securely held by their arms and should be tightened
at the first sign of looseness. The spring tension ad-
justing screws should be turned down tight when
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INDICATINO DEVICES AND TROUBLE LOCATION 239
properly adjusted and should be held in place by
lock-nuts or other fastening devices.
The Delco ampere-hour meter, Figure 105, should
have its contacts cleaned at long intervals. The only
other care required is that the large hand be lifted
up once every two weeks and turned twenty points
in a clockwise direction. The hand should never be
re-set past the number **70" on the dial, and if
twenty points movement would do this, the amount of
setting will have to be reduced. •
STARTING TROUBLES
The starting system consists of the motor, the start-
ing switch, the wiring and the driving parts. Elec-
trical trouble may be present in the motor, switch or
wiring and mechanical trouble may occur in the
driving mechanism.
The troubles outlined under the heading of the
dynamo in this chapter niay also be found in the start-
ing motor and their location and remedy will be cared
for in the same way as in the case of the djrnamo.
The starting switch contacts may be making poor
contacts because of wear, looseness or bending, or the
contact surfaces may be dirty or pitted from spark-
ing. The terminal connections of the large cables on
the starting switch should be examined for loose wire
strands, accidental grounds or short circuits, broken
or loose fastenings. The wiring is subject to the same
troubles as found in the charging or lighting circuits,
but because of the heavy conductors and thick insula-
tion used such faults will be of less common occur-
rence in the starting system than in other parts of
the equipment.
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240 STARTING AND LIGHTING.
The parts of the starter drive systems should be
kept clean and sliding surfaces should be lubricated
with heavy oil or by means of grease placed in the
cups. This lubrication should be cared for at least
every week if trouble is to be avoided. It may be
found that drive shafts have become bent through
binding or improper use of the starting pedal and
in some cases it will be found that gear shifting and
switch return springs are not heavy enough for the
work to be done, especially on new cars before the
parts have been fuUy worked in. Overruning clutches
should be lubricated with vaseline or rather thin
grease of good quality and the starting pedal should
never be held in the starting position long enough
to cause the clutch to be run at high speed. This will
surely result in burning the grease and the final
result will be a badly damaged or ruined clutch.
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CHAPTER VIII
MAKES AND TYPES OF EQUIPMENT
Following the names of the well-known makes of
automobile starting and lighting equipment will be
found a brief description of the types of starting and
lighting apparatus that have been made and mar-
keted by these companies.
p •:-. ■ -■■■ ■ .--'—■■--■ --^--I
^T^t^^^^^^^^^^F^^Si^^^H! If
Figure 106. — Auto-Lite Dynamo with Constant Speed Governor.
AUTO-LITE
Early models of Auto-Lite equipment comprise a
permanent magnet dynamo of the constant speed
type, Figure 106, fitted with a slipping clutch gov-
ernor at the drive end and carrying its electromag-
netic cut-out underneath the magnets and just above
241
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STARTING AND LIGHTING
the armature housing. This machine has been super-
seded by types that have electromagnetic fields car-
rying a compound winding with the series coil ar-
ranged to oppose the shunt, Figure 107, thus forming
a machine with reversed series regulation.
Auto-Lite dynamos have carried an ignition
breaker and distributor in some instances, but other
Figure 107. — ^Auto-Lite Dynamo Having Reversed Series Field
Windings.
combinations, such as motor-dynamos, have not been
used. The starting motors are straight series wound
units in all cases and, together with the dynamos,
operate at six volts.
DYNETO AND ENTZ
Until recently all machines of these makes have
been compound wound motor-dynamos operating at
a constant ratio of speed with the engine. The elec-
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MAKES AND TYPES OP EQUIPMENT
243
trie unit is directly eonneeted to the engine, usually
by means of a silent cfiain, and is placed in electrical
connection with the battery by means of a hand-
operated switch, no electromagnetic cut-out beijig em-
ployed. These single-unit machines. Figure 108,
have been made to operate with either twelve or
eighteen volts.
Figure 108.— Dyneto-Entz Motor-Dynamo.
A recent addition to the Dyneto line consists of a
separate dynamo and a motor, both operating at six
volts. The dynamo is connected with a separately
mounted controller which contains an electromag-
netic cut-out and a vibrating regulator that acts to
insert a resistance in the field circuit when the am-
perage reaches a certain maximum determined by the
adjustment of the regulator. The starting motor used
with this system is a series wound machine conforming
to the practice generally followed in such units.
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STARTING AND LIGHTING
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MAKES AND TYPES OF EQUIPMENT 245
GRAY & DAVIS
The first Gray & Davis equipments, Figure 109,
included a compound wound dynamo fitted with a
dipping clutch governor to limit the armature speed.
The series winding of these machines carries the
lamp current when any lights are in use, thus increas-
ing the djrnamo output in proportion to the load. An
electromagnetic cut-out is mounted on the dash or at
any other convenient point on the car, and the elec-
trical devices may be wired on the ground return
plan or by the use of a double-wire system throughout.
Later models of this make, Figure . 110, use a
dynamo of the shunt wound type having a vibrating
regulator with field resistance and an electromagnetic
cut-out mounted in one housing on top of or near the
dynamo. The starting motors used with separate
dynamos are of the series wound type in all cases and
all units operate at six volts. Gray & Davis have
recently added a single-armature motor-dynamo that
carries the same form of controller as the separate
dynamos just mentioned.
KEMY
Remy equipment includes separate dynamos and
motors, ignition dynamos, motor-dynamos, double
deck machines and motor-dynamos with ignition parts
mounted on the electric machine. With the excep-
tion of the twelve-volt motor-djrnamo, all of the types
make use of six- volt pressure for lighting, charging
and starting. Either a third-brush system or else a
vibrating regulator with field resistance have been
used in a majority of installations. The third-brush
machines, which class includes some of the double-
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246
STARTING AND LIGHTING
deck equipment as well as separate dynamos, make
use of an electromagnetic cut-out carried on the dy-
Flgure 110. — Gray & Davis Dynamo with Vibrating Regulator and
Cut-Out.
namo or mounted elsewhere on the car. The types
using the vibrating regulator, Figure 111, combine
the electromagnetic cut-out with the regulator in a
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MAKES AND TYPES OF EQUIPMENT
247
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248 STARTING AND LIGHTING
controller that may be carried above the dynamo or
separately mounted.
Ignition-dynamos carry a breaker and distributor
of the familiar magneto form at one end of the ma-
chine, and drive these parts from the extended arma-
ture shaft. In some cases a separate dynamo may be
fitted with a vertical type of ignition breaker and
distributor driven from the dynamo shaft. The start-
ing motors are of the series wound type and may
employ any one of several types of drive to the en-
gine. The wiring for all units may be carried out
on either the one or two-wire plan.
DELOO
The greater proportion of Delco equipment uses a
compound wound motor-dynamo. Some of the more
recent installations include separate dynamos having
a shunt field winding and used in connection with a
series wound starting motor. The earliest types con-
sist of a single-armature motor-dynamo having one
set of brushes for both starting and charging func-
tions. These systems, Figure 112, are fitted with a
twelve-cell battery of four sections, allowing twenty-
four volts for starting and six volts for charging and
lighting. These **6-24 volt'' systems carry the
ampere-hour meter regulator, described in Chapter V,
and an electromagnetic cut-out.
All of the later motor-djoiamo systems provide the
single armature with two commutators, two windings
and two pairs of brushes, one set of each being used
for starting and the other for charging. These ma-
chines all operate at six volts and are built with the
single-wire or grounded-return system in all cases.
With some types of this class an electromagnetic cut-
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MAKES AND TYPES* OP EQUIPMENT
249
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250
STARTING AND LIGHTING
out is fitted, Figure 113, while others make use of
additional contacts on the ignition switches for the
purpose of connecting the motor-dynamo as a dynamo
with the battery for charging. Regulating methods
have included the reversed series system, a centrifu-
gal governor. Figure 114, inserting a field resistance,
a mercury-well type of voltage regulator or a third-
brush control. Figure 115, for the shunt field current.
Figure 113. — Delco Cut-Ont
A — Contact Points. C — Magnet Armature.
5— Spring.
D — Magnet Core.
DISCO
The most commonly used Disco equipment consists
of a compound wound motor-dynamo direct connected
to the engine by chains or gears. This unit is fitted
with a controller comprising an electromagnetic cut-
out and a vibrating regulator acting to insert a re-
sistance in the shunt field circuit when the amperage
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BIAKES AND TYPES OF EQUIPMENT
251
AUTOMATIC
SPARK
CONTROL ^^
B
RECULATINC
RESISTANCE
RESISTANCE
ririitor H- \ \{
3 TIMER n i ^*^,, ', \|
MANUAL
SPARK CONTROL
Figure 114. — Delco Centrifugal Governor and Field Resistance.
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252
STARTING AND LIGHTING
gcnKator
BF?USM
GROUNDED
QnJSH
'^5?^r
Figure 115. — Delco Third-Brush for Dynamo Regulation.
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MAKES AND TYPES OF EQUIPMENT 253
is at the predetermined point. Disco systems of the
kind described operate at twelve volts and make use
of a single-wire connection for all circuits.
WESTES^GHOUSE
Three distinct types of Westinghouse dynamos are
in use. The form first adopted is a shunt wound
machine with an additional bucking coil, the flow
through which is lessened in proportion to the candle-
power of the lamps lighted while the dynamo is run-
ning. These dynamos carry an electromagnetic cut-
out at one end and may or may not be fitted with an
ignition breaker and distributor at the other. Almost
all dynamos of this class operate at six volts and cars
usiQg them generally are wired with a ground return
system.
Twelve-volt motor-dynamos are also a part of the
Westinghouse liQe, these machines being direct-oon-
nected to the engine at all times. The output is regu-
lated by a third brush for the shunt field current and
a separate electromagnetic cut-out may or may not
be used.
Later models of Westinghouse apparatus include
shunt wound dynamos with a self-contained or sep-
arately mounted controller consisting of an electro-
magnetic cut-out combined with a constant voltage
vibrating regulator that inserts resistance in the field
circuit when the voltage is at the correct point for
battery charging. See Figure 116.
Separate starting motors are of the series wound
type. They may be connected with the engine by
means of a Bendix screw drive, by an electromagnet-
ically operated starting switch and pinion shift, or
by means of a two-contact switch with sliding gears
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254
STARTING AND LIGHTING
that are revolved by the current sent through the
motor by the first contact of the switch, and after
■ To Bhtttiy. B-
Btgvloting Contccti
Voitagi titqttMineJernf
E
RtguMinq BiMtor.
— ^/W\AA^-
— w//, ^^^
*2l-2-.^_^^.|
Shunt Compvh a I
Mting Coif— * S L.
7l
Stfm
CoU
BtgylohrHiimlCoil
'SMmifttM
CommuMor
1
^•=-
Fljirure 110. — Connections of Westtnghouse Dvnamo with Self-Con-
tained Voltage Regulator and Cut-Out
being meshed crank the engine with the full current
allowed by the second switch position.
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B£AKBS AND Tix^c. Oji' HiVjUIFWfiNT 258
NORTH EAST
North East equipment consists of a motor-dynamo
operating as a motor at twelve, sixteen or twenty-four
volts and as a dynamo at six, eight or twelve volts.
These machines carry a single armature and set of
brushes and have compound wound fields. While
some of the earlier models were connected to the
engine through reduction gearing, a majority of these
equipments are direct-connected and operate at a
constant ratio of speed through silent chains or gears.
The dynamo housing encloses en electromagnetic
cut-out and a vibrating regulator that acts to limit
the amperage of the machine as a dynamo. Either
the single or double-wire system is used.
U.S. L.
All of the systems furnished by the United States
Light and Heating Corporation include a large size
motor-dynamo mounted directly on the engine crank-
shaft. The starting voltage may be either twelve or
twenty-four, while lighting and charging is cared for
at either six or twelve volts. Electromagnetic cut-outs
have been used on all types and in the earlier models
the cut-out is combined with an amperage regulator
consisting of a series of carbon dftics whose pressure
on each other is controlled by the tension of a coiled
spring which is allowed to increase or decrease
through the opposing strength of an electromagnet in
series with the charging lines. Later models of this
make of apparatus control the output of the electric
machine as a dynamo by means of field coils which
either assist or oppose the shunt windings, according
to the speed and output of the machine, F^gii^s: 117.
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256
STARTING AND LIGHTING
Figure 117,-7-U. S. h. Motor-Dynamo on Engine Crankshaft.
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MAKES AND TYPES OP EQUIPMENT
257
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M AaM<* 6 AnptM
r— O— O < O O .
FuM I Fhm
nRRPm
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C*6
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^
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ftSKD
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aha— J
-Bi:
4^iiiiiiiiiiy
Batterr
sililiKHl
Sid*
K>-f
JU:
a
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Figare 118. — Wiring for U. S. L. System Having Inherent
Beguiation.
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258
STARTING AND LIGHTING
a
00
s
«
I
§
1,
Oi
§
b
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MAKES AND TYPES OF EQUIPMENT
250
With the types that start at a high voltage, and use
a lower pressure for charging and lighting, a form
of commutating switch has been used which operates
in an oil bath. Wiring for charging and starting may
be on either the one or two-wire system, while light-
ing circuits may be of the one, two or three-wire
type. See Figure 118.
PUSH BUT TOM
Figure 120. — Wiring for Bljur System with Constant Voltage
Regulator.
BIJUB
Two types of dynamos and a motor-dynamo have
been marketed. Both of the separate dynamos are of
the shunt wound type, one operating on the third-
brush principle, Figure 119, and the other being a
constant voltage machine. Figure 120, controlled by
the action of a vibrating regulator for the field re-
sistance combined with an electromagiietic cut-out in
a housing attached to the top of the dynamo. The
third-brush dynamo is fitted with an electromagnetic
cut-out carried inside of the dynamo case. Separate
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200
STARTING AND LIGHTING
starting motors are of the series wound type and all
of the separate unit apparatus operates at six volts.
The motor-dynamo is a twelve-volt machine having
direct connection with the engine through a silent
chain. The output control is by third-brush action
Figure 121. — Wagner Starting Motor. L, M — Brush Holders.
for the shunt field current and the electric machine
is connected to the battery through a hand-operated
switch without the use of an elekitromagnetic cut-out.
WAGNER
The first models of Wagner equipment include a
motor-dynamo connected to the engine through a
chain and planetary gearing. This machine acts as a
starter at twelve volts pressure, and charges the bat-
tery at six volts. The commutating switch is mounted
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MAKES AND TYPES OF EQUIPMENT
261
on top of the unit and is in the same housing with
an electromagnetic cut-out. This machine is a com-
pound wound unit with third-brush regulation for the
shunt field current.
Later models of Wagner equipment make use of
separate dynamos and motors, the dynamos being
shunt wound with third-brush regulation, and the
motors, Figure 121, being of the usual series wound
form. The operating voltage for these separate unit
installations may be either six or twelve. "Wiring is
either single or double throughout.
Figure 122. — Bosch Dynamo for Use with Voltage Control.
BOSCH AND RUSHMOBE
The original Eushmore dynamo, and some of the
newer models of Bosch dynamos make use of the iron
wire controlled bucking field coil for regulation.
Otherwise these machines are of the shunt wound
type operating at either six or twelve volts and con-
nected by either a double or single wire system. An
electromagnetic cut-out is used in all cases, this unit
being mounted on the dynamo or on a separate panel.
One type of Bosch dynamo. Figure 122, is a con-
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STARTING AND LIGHTING
stant- voltage machine having a regulator whose re-
sistance is composed of carbon particles and mica.
This regulator is carried in a housing with the elec-
f-
i
■ 1
i—
^9,^^
t __J
I^^R^
1^
19
W
m
i
• 1
^'m^,^n
W
^^
Ej
.."^
Figure 123. — ^Arrangement of Rushmore Units on Engine.
tjfomagnetic cut-out and a voltmeter. These machines
are of the twelve- volt type.
Rashmore type starting motors are used with any
of the dynamos just described. . This form of starting
motor, Figure 123, causes the drive pinion to mesh
with the flywheel gear by means of the end motion of
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MAKES AND TYPES OP EQUIPMENT 203
the armature shaft induced through the pull of the
field magnets, this action having been described in
Chapter VI.
SPLITDORP
Splitdorf equipment includes a motor-dynamo, Fig-
ure 124, operating at twelve volts for both starting
Figure 124. — Splitdorf-Apelco Motor-Dynamo.
and charging or else at twelve volts for starting and
six volts for charging. In any case the unit is direct-
connected to the engine by means of a silent chain
and operates at a constant ratio of speed with the
engine.
The electric unit is compound wound and is con-
nected to the battery by means of a separately
mounted electromagnetic cut-out having a target ar-
ranged to show the words **OFP'' or **0N'' accord-
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264 STARTING AND LIGHTING
ing to whether the cut-out is open or closed respect-
ively.
The straight twelve-volt system makes use of a
single-contact starting switch, while the six-twelve
volt system uses a commutating switch to make the
proper connections between battery sections and
motor-dynamo. Either one or two-wire systems may
Figure 125. — Simms-Huif Motor-Dynamo.
be used, although the one-wire type is the one gen-
erally adopted.
SIMMS-HUPP
This equipment uses a compound wound motor-
dynamo, Figure 125, driven as a dynamo from the
engine through a flat belt and driving the engine as
a starting motor through sliding gears. A two-sec-
tion battery is connected with the electric machine
at twelve volts for starting and six volts for charging,
the necessary changes being accomplished with a com-
mutating switch.
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MAKES AND TYPES OF EQUIPMENT 265
Figure 126. — ^AlUs-Chalmers Motor-Dynamo.
E — Commutator. F Brush Holder. G, H — Pig-Tails.
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C9
S
0)
%
I
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MAKES AND TYPES OF EQUIPMENT 267
An electromagnetic cut-out combined with a vibrat-
ing regulator acting to insert field resistance is em-
ployed to control the action of the machine as a
dynamo. Further regulation is provided by the re-
versed series action of the series field winding while
the unit is generating. The one-wire system with
grounded return is used throughout the installation.
ALLIS-GHALMERS
The Allis-Chalmers equipments in general use con-
sist of a compound wound motor-dynamo, Figure 126,
operating at six volts under all conditions and directly
connected with the engine so that it runs at a con-
stant ratio of speed. The electric machine is con-
nected with the battery for charging by means of an
electromagnetic cut-out carried in the same housing
with a vibrating regulator that inserts resistance in
the shunt field when the correct amperage has been
reached. All circuits are of the single wire type.
See Figure 127.
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268
STARTING AND LIGHTING
Positive
Negative
Positive
or negative
+
±
Wires
crossing without .
connection
Connected wires ^ ^
Ground connection
Condenser .
^^
Battery
T
"5 9 Contact points
Wire terminal
Coil or solenoid
Electromagnet
AAAAA — . Coll or resistance
Lamps In multiple
®
Fuse
Voltmeter
Figure 128.— Symbols Used in Wiring Diagrams.
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CHAPTER IX
ELECTRICAL WORDS AND TERMS
A. O. — ^An abbreviation for alternating current. See Cur-
rent, Alternating,
Accumulator. — A storage battery. See Battery, Storage.
Add, Battery. — Chemically pure sulphuric acid having a
specific gravity of about 1.835, suitable for use in making
storage-battery electrolyte for lead cells.
Adapter. — A small threaded sleeve designed to screw into
a candelabra base so that a miniature bulb may be used.
Ammeter. — An instrument for measuring the rate of flow
of electric current directly in amperes.
Amperage, Constant. — Descriptive of a form of regulation
which allows the dynamo current to rise rapidly to a pre-
determined maximum and then causes the dynamo to main-
tain this value of current without much rise or fall at all
higher speeds.
Ampere. — The unit of current flow. Corresponds to gal-
lons per minute in measurement of water flow. The rate
of flow caused to pass through a circuit whose resistance
is one ohm by an electrical pressure of one volt.
Ampere-Hour. — The quantity of electric current that flows
during one hour through a circuit in which one ampere
is passing. Equals 3,600 coulombs. Used in measuring the
capacity of storage batteries, in which case a battery having
a capacity of 80 ampere-hours would be capable of main-
taining a flow of eight amperes for ten hours, ten amperes
for eight hours, or any other combination of hours and
amperes which multiplied together will result in eighty.
Ampere Turn. — One complete turn of a conductor in a
coil through which one ampere is passing. The amperage
multiplied by the number of turns in a coil gives the num-
ber of ampere-turns in that coil. The ampere turns of a
coil determine its magnetic strength and the same strength
269
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270 STAETIKG and LIGHTING
will always be developed by the same number of ampere
turns whether they result from a large number of turns
and few amperes or large amperage and few turns.
Arc. — ^The flash or spark between two parts of a con-
ducting path through which current is flowing when these
parts are caused to separate. Seen at cut-out contacts, reg-
ulator contacts, dynamo and motor brush contacts on their
commutators, etc.
Armatnre. — ^A piece of iron or steel so placed that it is
in the field of a magnet or is acted upon by the lines of
force of a magnet.
Armatnre, Dynamo or Motor. — ^A part of the machine
which consists of an . iron core on which is wound coils of
wire. In the case of a dynamo, the movement of these
eoils through the magnetic field causes voltage to be gen-
erated and a flow of current to result. In the case of a
motor the operating current, or part of it, is sent through
the armature windings and the result, together with the
effect of the fields, causes the reaction which results in
d^elivery of power from the motor. The armature is usually
the part of the machine that revolves, although in some
dynamos the armature is stationary and the fields are re-
volved.
Armature, Dram^ — ^A form of armature in which the wind-
ings pass from end to end of the iron core and around
the ends. The core is usually a solid mass of iron of cylin-
drical shape.
Armature, Magnet. — A small piece of iron or steel mounted
on a movable holder and carried near one end of an electro-
magnet. The armature is attracted to the magnet when-
ever current flows through the magnet windings. Attached
to the movable arms of cut-outs, regulator vibrators^ cir-
cuit breakers, etc.
Armature Reaction. — A term often used to describe the
effect of the rotating armature core in carrying the lines
of force of the field part way around in the direction of
revolution while the dynamo is in operation. With sta-
tionary brushes ' the • voltage between the points on the
commutator against which the brushes bear will vary with
the extent of this effect present. Utilized in "third brush
regulation. ' '
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ELECTRICAL WORDS AND TERMS 271
Armature, Bing. — Somej;imes called a ''Gramme" ring
armature. An armature whose windings are placed around
a circular or ring-shaped core. ^
Ballast Ck)iL — The length of iron wire inserted in the
charging circuit of Bushmore and some Bosch-Bushmore
dynamos which acts ;to send a part of the current around
the bucking field coil with excessive increase of current
generated.
Bar, Commutator. — See Segment,
Battery, Storage. — A number of storage cells placed to-
gether as a single unit and arranged to be connected with
each other to give th^ desired voltage for the circuits to
which the battery is attached.
Bayonet Base. — A form of lamp bulb socket of cylindrical
form and hollow with two or more lengthwise slots open
at the lamp end and ending in a turned over or hooked
portion of the slot at the other end. The cdrresponding
bulb base carries two or more projecting pins designed to
slide down into the slots and then engage with the hooked
portions by giving the bulb a part of a turn. The two
parts are then held together by the pressure of small
plungers or flat springs in the socket portion.
Bendiz Drive. — A form of starting motor drive which
causes a pinion carried on a threaded shaft attached to the
armature shaft to revolve on this threaded shaft and be-
cause of its travel along the threads to mesh with teeth
on the rim of the engine flywheel so that the power of the
starting motor is applied to crank the engine.
Brash. — ^Pieces of some conducting substance, usually car-
bon composition or copper, which bear on a moving sur-
face such as a commutator or the segments of a rheostat
and which collect or distribute current.
Backing Coil. — ^A winding placed on the field magnets
of a dynamo and which opposes the strength of the shunt
field winding whenever current is passed through the buck-
ing coil. Used to obtain regulation of dynamo output.
Buckling. — An action that takes place in the plates of a
storage cell which causes the entire ^late to bend or warp.
Bolb. — The glass part of an incandescent lamp. Often
used to designate the glass bulb with the filament and base.
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272 STARTING AND LIGHTING
Bus-Bar. — ^A strip of copper or brass which carries a num-
ber of terminals to which conductors and wires of an elec-
tric system may be attached.
Cable. — A condireting wire with its insulation. Usually
applied to such wires when they are of comparatively large
size.
Calibrate. — To. determine the accuracy of the indications
given by an electrical instrument such as a voltmeter or
ammeter and to note the error, if any, between the scale
divisions on the instrument being calibrated and another one
of known accuracy or with currents and voltages of known
value. Usually employed to designate the operation of
correcting the working of an instrument so that its indi-
cations are correct.
Candelabra. — The name given to the larger of the two
sizes of screw bases used for lamps employed in car lighting.
Candlepower. — The unit used in measuring the light given
by any source of illumination. One candlepower is the
light given by a standard candle made to burn a certain
definite quantity of spermaceti each minute and of stand-
ard dimensions and construction.
Capacity, Battery. — The number of ampere-hours discharge
that may be secured from a storage battery. It is affected
by the rate of discharge in amperes, by the voltage, spe-
cific gravity and condition of the plates in the cells, by
the temperature of the battery and by many other factors.
Carbon. — A chemical element. Found in graphite^ char-
coal, diamonds and fuel substances generally.
Cell, Storage. — A unit consisting of several positive plates
and several negatives with plates of like polarity connected
together and with the whole set immersed in a bath of elec-
trolyte and enclosed by a jar of insulating material. A
storage cell gives a voltage of approximately two, regard-
less of its size, but the capacity depends on the quantity
of material in the plates and the design of the battery
parts.
Charge. — ^The action of sending a flow of current through
a storage battery so that a chemical change is caused to
take place which results in the ability of the battery to
deliver current.
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ELECTRICAL WORDS AND TERMS 273
Circuit. — The complete path through which a current flows
from the time it* leaves the source until it returns to the
source. A circuit must always consist of three parts when
employed in electrical equipment; namely, the source which
may be the dynamo or the battery, the conductors which
consist of wires and connections for both positive and nega-
tive sides, and the receptive or current-consuming devices
which may consist of the lights, starting motor or other
equipment. A circuit must always start with and end with
the source, and if any portion of the circuit is incomplete
there can be no flow of current at any point or in any part
of the circuit.
Circuit Breaker. — A device consisting principally of elec-
tromagnets and current-carrying contacts which is designed
to open a circuit whenever the current flowing through it
exceeds a certain value. This name is often applied to a
cut-out, although a circuit breaker and a cut-out do not per-
form similar duties.
Circuit, Closed. — A circuit' that is complete from the
source to the current-consuming devices and from these
devices back to the source and through which a current
can flow.
Circuit, Grounded. — A circuit which is completed through
the metal work of the car. The metal work takes the place
of any other conductor for a certain portion of the path.
Circuit, Open. — A conducting path which is not complete
from the source of current to the current-consuming devices
and back to the source. No current can flow through a
circuit that is open at any point in its path.
Circuit, Short. — A connection between two wires or con-
ductors of opposite polarity that allows the current flow-
ing from the source to complete a path back to the source
without going through the current-consuming devices or
without doing the work that it should were the current
forced to pass through the whole circuit. Should a current-
carrying conductor of one polarity come into contact with
the frame or metal work of the car when this metal work
forms a part of the circuit of opposite polarity from the
first conductor, a form of short circuit called a 'Aground"
is formed.
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274 STARTING AND LIGHTING
Clips, Fuse. — The small spring or screw holders which
carry a cartridge fuse.
Clutch, Overrunning. — ^A device consisting of. two parts,
one driven from the starting motor and the other driving
to the engine to be cranked, with these parts arranged to
be held together by wedging rollers when the starting motor
drives the engine, but so arranged that the rollers will
release and allow the engine to run free when its speed ex-
ceeds that at which the starting motor can drive it.
C. O. D. Indicator. — See Indicator,
Coll. — One turn or a number of turns of wire surrounding
a central core usually of iron or wound on a support that
allows a hollow space through the center of the coil.
Coll, Compensating. — The name applied to one of the
windings on one of the field magnets in the U. S. L. motor-
dynamo. The function of this winding is to control the
dynamo • output by assisting the shunt field at low speeds
and by opposing the shunt at high speeds.
Commutator.^— The series ot segments attached to the
armature windings of a direct current dynamo or motor
and on which the brushes bear. The segments pass under-
neath the brushes at such a time that the alternating cur-
rent produced in the armature windings is changed into a
direct current for use in the outside circuits.
Compound Winding. — See Winding, Compound.
Condenser. — A number of sheets of some thin conductor,
usually tin foil, placed one on top of another but separated
by some insulating material such as mica or waxed paper.
The sheets of conductor are connected in two sets, every
alternate sheet being fastened to one lead and those be-
tween to the other lead. The condenser is placed so that
one lead attaches to one current-breaking contact while the
other lead attaches to the other contact. A part of the
electricity that would ordinarily result in a spark at the
time the contacts separate, passes into the condenser and
remains there until the contacts again close, at which time
this electricity from the condenser adds its effect to that
passing through the contacts.
Conductor. — Any material or substance through which the
electric current can pass with ease. All metals and many
liquids are good conductors.
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ELECTRICAL WORDS AND TERMS 275
Oondnctivlty. — ^The opposite of resistance. A measure of
the readiness or ease with which current can pass through
a conductor. The higher the resistance to passage of cur*
rent becomes, the less will the conductivity become.
Conduit. — ^A tubular protecting covering for electric wir-
ing generally made from metal and either flexible or rigid.
Connector. — A device for completing one or both sides
of a circuit by means of pin plungers carried by one part
of the connector and designed to fit into holes in the other
part of the device. The ends of the circuity wires are
fastened to the pin at one side and to the metal lining of
the hole at the other.
Constant Amperage or Voltage. — See Amperage, Constant^
and Voltage, Constant,
Contacts. — Small pieces of heat and spark-resisting con-
ductor, usually metal or carbon, that carry the current flow-
ing through a circuit when two of the contacts are touching
each other and which act to break the circuit when they
are drawn apart.
ControL — ^The action of limiting the current delivered
from a dynamo and of preventing the current in the charg-
ing circuits from taking improper paths. Control is ef-
fected by the current regulating system and by the cut-out.
Controller. — An electromagnetic cut-out and a current out-
put or voltage regulating device carried in one case or
combined with each other so that some of their parts func-
tion with both units.
Core. — ^The iron form upon which coils of wire are car-
ried or wound in forming electromagnets, dynamo or motor
fleld magnets, armatures, etc.
Corrosion. — The action of acids or alkalies upon metal or
the substance formed by this action. Found on the ter-
minal connections of storage batteries and between the
metal of their grids and the active material of the plates.
Coulomb. — A unit which measures electrical quantity and
whose value is 1/3600 of an ampere-hour. A coulomb is
the quantity of electricity that passes through a circuit in
one second it, the rate of flow is one ampere.
Current. — The rate of flow or the quantity of electricity
that is passing through a circuit. Current flow ^ meas-
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276 STARTING AND LIGHTING
ured in amperes and is increased with increase of pressure
or voltage and is decreased by increase of resistance.
Current, Alternating. — A current which reverses its di-
rection of flow or its polarity at regular intervals. Alter-
nating current is generated by all dynamos and in direct
current dynamos the alternating current is changed to di-
rect current by the commutator.
Current, Continuous. — Direct Current (which see).
Current, Direct. — A current which always flows in the
same direction through its circuit and which would cause
conductors through which it flows to remain of the same
polarity at all times.
Current, Eddy. — Currents produced in the iron cores of
the armature and field magnets of motors and dynamos
by the motion of these parts in a magnetic field or by the
motion of magnetic lines of force about them.
Current, Pulsating. — ^A current whose value rises and falls
suddenly.
Cut-In. — ^The closing of the charging circuit by the cut-
out when its contacts come together. Cut-in time means
the engine or armature speed at which this action takes
place.
Cut-out. — A switch through which the charging circuit
from dynamo to battery is completed. When the cut-out
is open there can be no flow through the charging cir-
cuit, either from dynamo to battery or from the battery
through the dynamo. When the cut-out is closed a cur-
rent may flow in either direction and the direction of flow
will be from the unit having the higher voltage to the one-
of lower voltage.
Cut-out, Electromagnetic. — A cut-out switch whose cur-
rent-carrying contacts are closed by the magnetic strength
of an electromagnet through the windings of which current
flows from the dynamo and whose strength is determined by
the voltage generated by the dynamo. The contacts are
opened and held open by the action of a spring or by the
force of gravity which opposes the electromagnet.
Cut-out, Hand or Manual. — ^A cut-out switch operateid by
the driver of the car and so connected with either the
ignition or starting switches that the cut-out will be open
whenever the engine is idle or the ignition turned off and
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ELECTRICAL WORDS AND TERMS 2T7
will be dosed by the closing of the starting switch or by
the closing or turning on of the ignition switch.
D. C. — ^Direct Current. See Cwrrent, Direct,
Discharge^ — ^The flow of current from a storage battery
to and through the outside circuits. Any flow which causes
the capacity of the battery to decrease. Any flow whose
direction is away from the positive terminals of the bat-
tery and into the negative.
Distribution PaneL — See FwmA, IHstribution.
Double Contact. — A name descriptive of a lamp bulb whose
base carries two metallic points through which current en-
ters and leaves the bulb. Also applied te a base designed
to receive such a bulb.
Double Deck. — ^A motor and a dynamo which form sep-
arate units electrically but which are mechanically fastened
together with one above the oth.er either in one housing
or in separate cases. *
Double Wire. — See Two-Wire System.
Dynamo. — ^An electric machine which changes mechanical
power into electric current.
Ediswan. — See Bayonet.
Ef&ciency. — The amount of useful work or power that
may be taken from a device in proportion to the power or
work of some other form that is consumed by the device
while working. The efficiency of a storage battery is the
percentage of ampere-hours' discharge that may be secured
in comparison with the number of ampere-hours' charge
that is given. The efficiency of a dynamo is the percentage
of current that it delivers in proportion to the power it
requires to drive the dynamo while delivering that current.
The efficiency cf an electric motor is the percentage of
power delivered in proportion to the flow and pressure of
electricity that the motor requires in order to deliver that
power.
Electricity. — The name given to the cause of electrical
effects of all kinds.
Electromagnet. — A magnet made from a core of soft iron
and magnetized by the passage of a current of electricity
through a coil of wire surrounding the core.
Electromotive Force.— Electrical pressure, potential or
voltage. Ability to do work.
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278 STARTING AND lilGHTING
Energize. — ^In speaking of a coil or magnet this means
that the coil or magnet receives current and produces mag-
netism.
Faure Plate. — A pasted plate for a storage battery. See
Flate, Pasted,
Field. — The space around the poles of a magnet through
which the magnetism or magnetic lines ot force of the
magnet will produce certain effects is called the field of the
magnet. As the word is ordinarily used it means the field
winding or the field winding and magnet core of a dynamo
or motor.
Filament. — The conductor carried inside of the bulb of
a lamp and which gives light when heated to incandescence
by the passage of current against its resistance and through
its length.
Finish Bate. — The number of amperes that may safely
be passed through a storage battery for a period of from
eight to twenty-four hours in completely charging the cells.
Same as twenty-four rate. Depends on the ampere-hour
capacity of the battery and is usually a number of amperes
that corresponds to about one-twentieth of the ampere-hour
capacity.
Floating. — ^Placing a battery in a lighting and starting
system so that one side of the circuit includes and attaches
to the positive terminal of the battery, of the dynamo, of
the lamps and of the starting motor, and so that the other
side of the circuit attaches to the negative terminals of
these units. The battery may then receive current from
the dynamo when the dynamo output is above the current
required by the lamps, etc., and will give the required ad-
ditional amount of current to the circuit whenever the
dynamo output is less than the requirements of the current-
consuming devices. The battery acts as a reservoir into
which any excess current passes and from which any de-
ficiency may be drawn.
Foot Ponnd. — See Pound, Foot,
Formed. — The condition of storage battery plates after
the material in their plates has been changed to peroxide
of lead for t^e positive and to sponge lead for the negative
by the passage of a charging current and by intervening
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ELECTRICAL WORDS AND TERMS 279
discharges sufficient in number and time to produce this
effect.
Fuse. — A short length of wire of various compositions
which is so proportioned and made that it will carry any
amperage up to a certain predetermined maximum, but will
heat to the melting point and separate when this current
is exceeded, thus breaking the circuit protected by the
fuse.
Fuse, Cartridge. — ^A fuse enclosed in a tube, generally
made from fibre or glass and capped with metal at each
end so that when placed in fuse clips the current may pass
from the clips through the caps and through the fuse. Used
when it is desired to avoid a spark in the open air.
Fuse, Field. — A fuse placed in the circuit of the field
windings of a dynamo and of such a capacity that it will
melt and open the field circuit when the amperage reaches
a point beyond which there would be danger of burning
out the field windings themselves.
Fuse, Link. — An unenclosed fuse wire.
Oap, Air. — The distance between the end or pole of a
magnet and the iron of the magnet's armature which may
be the iron of the dynamo or motor armature core or the
armature piece of an electromagnet.
Oassing. — ^The evolution of hydrogen and oxygen gases
from the water in the electrolyte of a storage cell caused by
the passage of charging current through the cell.
Oear. — ^The larger one of two toothed wheels which are in
mesh. The smaller one is called the pinion.
Oear, HelicaL— A gear having its teeth of such form that
they slant across the face. If such a gear were wide
enough across the teeth or long enough in the direction of
its hub and axis, the teeth would form complete turns
around it.
Generator. — ^A name sometimes applied to a dynamo.
Gramme Bing Armature.— See Armature, Eing.
Gravity. — See Specific Gravity,
Grid. — The metallic framework which supports the active
material and which with the active material forms a plate
of a storage cell.
Ground. — The name applied to the metal parts of a car.
The 'Aground'' or metal is used to complete one side of
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280 STARTING AND LIGIJTING
the eircuits in a one-wire system. Whenever a eonductor
or an electrical device is in metallic and electrical connec-
tion with the metal parts of the car the conductor or de-
vice is said to be '^ grounded" to the part on which it at-
taches or is mounted. See also. Circuit, Grounded and Cir-
cuit, Short.
Oroimd Beturn. — A name applied to a one-wire system
or a system in which a part of either the positive or nega-
tive side of some or all of the circuits is completed through
the metal work of the car.
Holder, BnulL — The part of a dynamo, motor, rheostat,
etc., to which the brushes are fastened or in which the
brushes are carried. The holder may be rigidly mounted
or may be carried on pivot bearings.
Horsepower. — The rate at which work is done when 33,000
pounds is raised to a height of one foot in one minute.
Provided this amount of work has been done in one minute
one horsepower is being expended. To do the same amount
of work in one-half the time would require twice the me-
chanical power or two horsepower of effort although the
total amount of work done would remain the same. An
electrical horsepower equals 746 watts. The horsepower
that a current is capable of developing may be found by
multiplying the number of volts by the number of amperes
to find the number of watts and then by dividing this
number of watts by 746, which will give the number of
horsepower or the fraction of one horsepower.
Hydrometer. — A device for finding the weight of a liquid
in relation to the weight of water. The usual form of
hydrometer consists of a glass tube weighted at the lower
end, having an air bulb above the weight and carrying
a thin extension or tube above the air bulb. The hy-
drometer will sink into any liquid to a point on the ex-
tended tube or stem that corresponds to the weight of that
liquid. The stem is graduated according to the specific
gravity scale which assumes water to be unity and repre-
sented by 1.000. A liquid twice as heavy as water would
then have a specific gravity of 2.000, etc. The point on
the scale carried by the stem to which the hydrometer sinks
indicates the weight or specific gravity of the liquid in
which it is floating. See Specific Gravity.
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ELECTRICAL WQRPJ5 AND TERMS 281
Hydrometer Syringe. — A glass tube containing a hydrom-
eter and into which a liquid to be tested may be drawn
through a nozzle at the lower end of the tube. The upper
end of, th^ tube carries a rubber bulb which may be com-
pressed to afford the suction necessary in drawing liquid
into the tube.
Ignition-Dynamo. — A dynamo which carries an ignition
breaker and distributor driven from the dynamo shaft and
designed to make use of current from the dynamo or the
storage battery charged from the dynaipo.
Indicator. — A device which indicates flow of current
through a circuit in which it is placed and shows in which
direction the current is traveling. Some indicators have n
hand like an ammeter, this hand swinging to words such
as ** Charge" when the battery is receiving current, '*Off"
when there is no flow into or out of the battery, and ** Dis-
charge" when current flows from the battery. In some
forms the words themselves move into view according to the
conditions existing. These instruments are often called
'*C. O. D. Indicators."
Induction.— The production of electrical pressure in con-
ductors which are moved into and out of a magnetic field
or which are allowed to remain stationary while a magnetic
field in which they lie alternately increases and decreases.
Induction is brought about when conductors move through
lines of force or when lines of force move across a con-
ductor. The current that is caused to flow in the conduc-
tor by the pressure is often called an induced current.
Inertia Pinion. — A starting motor drive operating on the
same principle as the Bendix Drive, which see.
Inherent. — Some effect in a machine that is a natural re-
sult of the design and construction used in the machine and
that does not require the use of external or additional mov-
ing parts to accomplish the result. Uged to describe cer-
tain forms of regulation, especially reversed series systems
in which it is the direction of winding the series coil that
produces the inherent regulation.
Insulated Betum. — A name applied to a one-wire system,
which see.
Insulation. — Material that is a non-conductor of electricity
and that is used in connection with conductors to prevent
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282 STARTING AND LIGHTING
current passing from the conductor at any point where such
passage is not desired.
Iron Wire OontroL — A system of regulation used with
Bushmore and some Bosch-Bushmore dynamos by which, a
length of iron wire is made to send current through a buck-
ing field coil by the heating of the iron with passage of
excessive current through it.
Jar, Battery. — A receptacle made from a material that
will carry liquids without leakage and which is an elec-
trical insulator. The plates and electrolyte of storage cells
are placed in the jar.
Junction. — ^A terminal connection, often enclosed, at which
a <^ircuit divides into two or more parts.
Keeper, Magnet. — A small piece of iron or steel placed
across the poles or ends of a permanent magnet and af-
fording a path through which the magnetic circuit may be
completed.
Kilowatt. — ^One thousand watts. Approximately 1% horse-
power.
Lead, Peroxide of. — The chemical substance formed by
the combination of one part of metallic lead with two
parts of oxygen.
Lead, Sponge. — ^Pure metallic lead of a porous or spongy
form.
Lead, Sulphate of. — The chemical substance formed by
the combination of one part of metallic lead with one part
of sulphur and four parts of oxygen.
Lines of Force. — ^The paths taken by the magnetism
around the poles and in the fields of magnets.
Load. — ^The resistance placed in a circuit and through
which current passing in that circuit must flow. The load
may take the form of lamps, starting motor or any other
current-consuming device.
Magnet. — ^A material possessing the power of attracting
other magnetic bodies or iron and steel. A material hav-
ing a field of magnetic lines of force. For practical pur-
poses magnets may be made only from iron or steel.
Magnet, Compound. — Two or more single magnets placed
together so that their like poles are side by side.
Magnet, Electro. — See Electromagnet,
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BliBCTRJCAL WORDS AND TERMS 283
Magnet, Permanent. — A magnet made from hard steel and
which remains magnetic for igng periods of time under or-
dinary conditions of use.
Mi^rnetic Unas of Force. — See Lines of Force,
Magnetism. — ^The condition of a magnetic material or a
coil when they are surrounded by a field of magnetic lines
of force.
Magnetism, Besldual. — A slight magnetism that remains
in any piece of iron or steel after it has been once mag-
netized.
Manual Cut-out. — See Cut-out, Hand or Manual.
Marker Bulb. — A small bulb carried by one of the large
lamps of a car but outside of the focal point of the reflector.
Also called pilot or dimmer bulbs.
Material^ Active. — The paste formed from compounds of
lead mixed with dilute sulphuric acid which is used to fill
the grids of storage cells in making plates.
Mercury Well. — A voltage regulator used with some types
of Delco equipment in which a resistance in the field cir-
cuit is more or less short-circuited by a bath of mercury.
Meter, Ampere-Hour. — A device that measures and indi-
cates the quantity of electric current passing into or out
of the storage battery. Used in connection with the regu-
lating system of some Delco equipments.
Miniature. — ^The smallest size of screw base for incan-
descent lamps.
Motor. — ^An electric machine that changes electric cur-
rent into mechanical power.
Motor-Dsmamo. — ^An electric machine having one arma-
ture core with either one or two windings; one or two
commutators and one set of field cores with two or more
windings, which acts either as a dynamo or motor, accord-
ing to whether it is supplied with power or electric current.
Multiple. — ^A form of circuit in which two or more sources
of current or two or more current-consuming devices have
their positive terminals connected together and their nega-
tives connected together.
Negative. — See Polarity.
Neutral Wire. — ^A wire connected to each of two sources
of current, either batteries or dynamos, so that current
may flow in either direction through the wire according
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284 STARTING AND LIGHTING
to which one of the two sources is being drawn upon for
the greater amount of current. When the load is evenly
divided between each source the neutral wire carries no
current.
Kitrogen Bulb. — ^An incandescent lamp bulb in which the
air has been replaced by the gas nitrogen.
Ohm. — The unit of the resistance to the passage of elec-
tricity. An ohm is the resistance that will allow one am-
pere of current to flow in a circuit when the pressure is one
volt.
Ohm's Law. — ^The relation between electrical pressure,
current flow and resistance is expressed by Qhm's Law as
follows: The current or amperage equals the voltage di-
vided by the resistance in ohms; the voltage equals the
amperes of current multiplied by the resistance in ohms;
the resistance may be found in ohms by dividing the voltage
by the current in amperes; When C represents amperes,
E represents volts and E represents ohms, the law may be
expressed by the equations:
E E
C=- E = CXR R = -
B C
One-Unit System. — An electric starting, lighting and ig-
nition installation in which an ignition breaker and dis-
tributor is combined with & motor-dynamo thus allowing
one unit to perform the three functions of lighting, starting
and ignition. ^
One-Wire System. — A method of connection in which one
side, either posit^ive or negative, of all or part of the elec-
trical devices and conductors is attached to the metal or
ground of the car and in which the metal is used as a con-
ductor to complete these circuits.
Open. — See Circuit, Open,
Output. — ^The number of amperes or the number of watts
furnished by an electrical source such as a dynamo or
battery.
Overrunning Clutcli.— See CZtitc^, Overrunning.
Panel, Distribution. — A body or plate of insulating ma-
^— ^* ^^ which lead the conductors for several circuits and
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ELECTRICAL WORDS AND TERMS 285
which carries suitable terminal connections and suitable
internal and external wiring to allow the circuits to bo
completed in their proper paths. Used to centralize the
wiring and connections of the electrical system.
Parabolic Belleetord — A reflector whose surface is so
shaped that a section cutting from side to side and through
the center would form a parabola. This form causes the
light reflected from a source of illumination placed in the
fucus of t^e parabola to be thrown in parallel rays and
straight ahead in the direction of the axis of the parabola.
ParaUeL — See Multiple.
Paste, Battery Plate. — The fllling for the grids of storage
cell plates. See MateriiU, Active,
Peroxide of Lead. — See Lead, Peroxide of.
Pig-TaiL — A short flexible wire that forms the electrical
connection between a brush and the conductor that carries
current to or from the brush.
Pilot Lamp. — A lamp placed in a charging circuit in such
a way that it lights when the cut-out closes and remains
lighted while the cut-out remains closed. Also used to des-
ignate a Marker Bulb, which see.
Pinion. — The smaller of two toothed wheels which are in
mesh. The larger one is called the gear.
Plate, Battery. — One of the units entering into a storage
battery cell. The plate is formed of a metal framework or
grid whose spaces are filled with active material formed
from a paste of compounds of lead mixed with dilute sul-
phuric acid. After forming, the material of the positive
plate is peroxide of lead and that of the negative plate is
sponge lead.
Plate, Pasted. — ^A plate conforming to the foregoing defi-
nition of Battery Plate as distinguished from plates formed
from pure metallic lead which has been acted upon by the
passage of charging current to change the surfaces into
peroxide of lead and sponge lead for the positive and nega-
tive respectively. Sometimes called a Faure plate from
the name of its inventor.
Plug, Vent. — ^A small screw or clamping plug placed in
the opening of each cell of a battery and by means of
openings in which the gases evolved during charging may
escape.
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286 STARTING AND LIGHTING
Point. — One-thousandth of a specific gravity unit or 0.001.
The difference between a specific gravity of 1.251 and 1.252
is one point, between 1.250 and 1.275 is twenty-five points,
etc.
Polarity. — ^The direction in which electrical pressure tends
to cause movement of a current determines the polarity.
It is assumed that the earth forms a reservoir of electricity
which does not tend to fiow. When current flows to the
earth the poiarity of the conductor through which it passes
and the earth end of the conductor is said to be positive.
When current flows from the earth to a conductor and
through the conductor the end of the conductor at which
the current enters and the conductor itself is said to be of
negative polarity. Current having positive polarity will
flow in one direction and will pass to a conductor of nega-
tive polarity, while current from a negative conductor will
not fiow to one of positive polarity.
Should a positive conductor having a pressure of eight
volts be attached to the end of another positive having a
pressure of only six volts, the first will be positive to the
second while the second, which was called positive, will
become negative to the first conductor. Had the conductor
with six volts pressure been connected to another having
only four volts, the six-volt line would be positive to the
four-volt, and the four-volt line would become negative to
the six-volt. In this case the conductor having the higher
voltage or pressure will be positive while the one of lower
voltage will be negative.
In the case of a source of electricity, the terminal or
end from which current is supposed to flow is called the
positive terminal, while the terminal into which current flows
is called the negative. Current flow is always from posi-
tive to negative and from a higher voltage to a lower.
Wires attached to a positive terminal are called positive
wires until they reach the current-consuming device or the
outer end of the circuit. Wires from the consuming-device
to the source and attaching to the negative terminal at the
source are' called negatiye wires.
Magnetic polarity is used to distinguish the ends or poles
of a magnet and is determined according to the direction
of movement of the magnetic lines of force. The pole
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ELECTRICAL WORDS AND TERMS 287
from which the lines of force leave the body of the mag-
net is called the positive or North pole and is designated
by a plus sign, -}~* '^^^ pole at which the lines of force re-
enter the body of the magnet is called the negative or
South pole and is designated by the minus sign, — .
Pole, Dynamo or Motor. — The ends of the field magnet
cores that are presented to the armature and which form
the walls of the armature tunnel. An electric machine hav-
ing two field magnet cores is called a two-pole machine, one
with four magnet cores or fields is called a four-pole ma-
chine, and so on, for any number.
Pole, Consequent. — A magnet pole formed when two ends
of the same polarity, either positive or negative, are placed
together, or a pole formed when two windings act to pro-
duce like poles at some point in a piece of iron located
between the windings. In the case of a dynamo or motor
the iron at the consequent pole is shaped to form a part
of the armature tunnel but carries no windings.
Pole Piece. — A piece of iron or mild steel fastened to the
end of a field magnet core and so shaped on its armature
side as to form the curve of the armature tunnel.
Positive. — See Polarity.
Potential. — A term having the same meaning as voltage
or electromotive force. The difference of electrical pressure
between two points is their difference in potential. Poten-
tial is measured in volts.
Pound, Foot. — The work required to raise a weight of one
pound to a height of one foot.
Pressure, ElectricaL — The force that acts to send current
through a circuit against the resistance o^ the circuit. Also
called Potential and Electromotive Force. Measured in
Volts.
Primary. — The winding of a transformer or ignition coil
that receives the current from the battery or dynamo at
low voltage and through the action of which on a magnetic
core is produced the current of high voltage used for igni-
tion. The wiring of the ignition circuits through which cur-
rent of low voltage passes is called the primary wiring. A
primary cell or battery is one which produces electric
current by chemical action and in which this action can
not be reversed as it can be in the storage cell.
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288 STARTING AND LIGHTING
Bectifier. — A device which changes an alternating current
to a direct current. '
Begulation. — The action of limiting or controlling the
amperage, or voltage, or both amperage and voltage, of a
dynamo.
Belay. — A device which closes or opens a circuit when
the voltage or amperage rises to a certain value in a second
circuit. A relay consists of an electromagnet through whose
windings flows the current that controls the action of the
relay and the time at which it will. close a circuit, or open
a circuit depending on its construction. When the relay
is designed to close a circuit the armature of its magnet
brings a movable contact to a stationary one and the circuit .
to be closed is completed through these contacts. When the
relay is designed to open a circuit the movable and stationary
contacts are so placed in relation to each other that movement
of the relay magnet armature draws the contacts apart and
opens a circuit that has been completed through the contacts.
The word relay is often used to designate a cut-out or a
regulator when these devices are electromagnetically
operated.
Beversed Series. — A series winding placed on the field
magnets of a dynamo and through which all of the current
flowing from the dynamo passes in such a direction that the
magnetic effect produced opposes the effect of the shunt
field winding.
Bheostat. — A resistance or a number of resistances in se-
ries with each other whose effect in a circuit may be readily
varied by changing the length or proportion of the resistance
inserted in the circuit.
Section, Battery. — A part of a complete battery consist-
ing of a number of cells arranged permanently in series
with each other and having one positive and one negative
terminal through which the section or series of cells may
be connected with the outside circuits or with other sections
of the battery in either a series or multiple circuit.
Segment. — A contact piece against which the brush of a
motor, a dynamo or a rheostat bears and to which is at-
tached one or more wires from the windings or resistances
of these units.
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ELECTRICAL WORDS AND TERMS 289
Separator. — A sheet of insulating material, usually formed
from specially prepared wood or hard rubber, which is used
between adjoining plates in a storage cell so that these
plates may not come into electrical connection with each
other except at their lugs.
Series. — A connection of conductors made between sev-
eral sources of current or between several current consum-
ing devices in such a way that all of the current that passes
through any pne unit or conductor will also have to pass
through every other unit and conductor in the series circuit.
In the case of units having terminals of definite polarity
the positive of one will be connected with the negative of
the next one in the circuit and the positive of this second
unit with the negative of the third, etc. See also Winding,
Series.
S. G. — ^An abbreviation for Specific Gravity, which see.
Short. — See Circuit, Short,
Shunt. — A path of a circuit through which only a part of
the whole current flows, the balance passing through one
or more additional paths whose ends attach to the same
source. When two conductors or two current-carrying de-
vices are attached to a source of current so that there is a
direct metallic path from each conductor or each device^
to each terminal, positive and negative, of the source^ each
part is called a shunt of the other one and the circuit from
the source through either path and back to the source is
said to be a shunt circuit. Any circuit in which part of the
current may take one path while other parts take other
paths consists of or contains shunts. Mutiple and parallel
connections are forms of shunt circuits. See also Winding,
Shunt,
Single-Contact. — A name descriptive of a lamp bulb whose
base carries but one metallic point through which current
may enter or leave the filament, the other side of the cir-
cuit being completed through the shell of the base. Also
applied to a lamp base designed to receive such a bulb.
Single-Unit System.— See One-Unit System,
Single-Wire System. — See One-Wire System,
Solenoid.— A coil of wire "without a metallic core, but
through which a current may pass and which will produce
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290 STARTIJ»G AND LIGHTING
magnetic effects and a magnetic fleld when a cnrrent does
pass.
Specific Ghravltyd — A measure of the weight of a liquid
which is expressed in decimal fractions or multiples of the
weight of an equal volume of pure water. The specific
gravity of water is assumed as unity or 1.000. Any liquid
one-half as heavy as water will then have a specific gravity
of 0.500, while a liquid twice as heavy will have a specific
gravity of 2.000 and one, one and one-half times as heavy
will have a specific gravity of 1.500. See also Hydrometer.
Speed, CriticaL — The speed of a car in miles per hour, of a
dynamo armature in revolutions per minute, etc., at which
some certain action will take place in some part of the
electrical equipment. The speed at which a cut-out will
open or close, at which a motor-dynamo will maintain a
voltage equal to that of the battery without charge or dis*
charge and at which a speed regulator will act are all criti-
cal speeds for those particular actions.
Sponge Lead. — See Lead, Sponge,
Start Bate. — ^In battery charging, the rate of flow or am-
perage which may be passed through the battery for the
first hour of charge from a separate source, or the maximum
rate that may be safely maintained by the dynamo on the
car.
Stop Charge. — ^Descriptive of any device, such as a relay,
that acts to open the fleld circuit or perform some other
action that will result in stopping the flow of current from
the dynamo.
Storage Battery. — See Battery, Storage,
Sulphate of Lead. — See Lead, Sulphate of,
Sulphated. — ^The condition of a storage battery plate when
its surface has become covered with a thick formation of
crystals of lead sulphate which prevent normal charge and
discharge of the cells affected.
Sulphuric Acid. — The acid used in making storage battery
electrolyte. It is composed of two parts of hydrogen, one
of sulphur and four of oxygen and is a heavy oily liquid
which will rapidly corrode and eat away most materials and
will produce severe bums on the flesh. It has a specific
gravity of 1.835 for the kind usually employed in battery
work. For such use this acid must be chemically pure.
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ELECTRICAL WORDS AND TERMS 291
commercial acid not being suitable. Its action on the flesh
or clothing may be stopped by the fr^e and immediate
application of strong ammonia water.
Switch, Commutating. — A form of switch connected to a
battery composed of several sections and which places the
sections in series with each other to produce a high volt-
age for starting while it connects them in multiple for
charging and lighting.
Tandem. — A mechanical connection of two electric ma-
chines such as a dynamo and motor, a dynamo and magneto,
etc., so that one shaft drives them both by passing through
one unit and extending to the drive end of the other.
Tapering Charge. — A storage battery charge that de-
creases in amperage in direct proportion to the rise of
voltage of the battery cells. A tapering charge is given
by a dynamo whose voltage remains constant because the
difference of voltage between dynamo and battery will be
great at the beginning of the charge when the battery volt-
age is low, and will become less and less as the voltage
of the battery more nearly approaches that of the dynamo
as charging progresses.
Target. — A visible indicator or marker attached to the
moving part of a cut-out or to the armature of a magnet
whose winding forms part of the charging circuit. The
marker will move into view when the cut-out closes or when
current flows through the charging circuit.
Three-Unit System. — ^An electrical installation in which
the starting motor, the dynamo and the ignition device are
all separate and distinct units with no parts in common.
Three- Wire System. — A form of connection or circuit, used
for lighting with which two sets of lamps having different
voltages may be operated from one battery or by means of
which two sets of lamps are attached to two sections of a
battery by means of three wires in place of four, the neutral
wire acting for either set and being attached to both sec-
tions of the battery.
Third Brash.-r-A brush bearing on the commutator of a
dynamo at a point somewhat distant from one of the main
brushes and through which current flows to one end of the
shunt field winding. The position of the third brush on the
commutator determines the amount of current flowing ■
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292 STARTING AND LIGHTING
through the field and the voltage acting at this brush varies
in s,uch a way that a rise followed by a fall of voltage
and current is obtained with constantly increasing arma-
ture speed. Forms a method of regulation.
Torque. — The rotative or twisting power exerted by a
shaft.
Touring Switch. — A switch placed in the charging or field
circuit or in both of these circuits so that when the switch
is opened the charge to the battery will be stopped as may
be desirable with a fully charged battery.
Trs^nsfonqer Coil. — A piagnetic core around which are
wound two separate coils having different lengths and sizes
of wire in each coil. Passage of a current which is pulsat-
ing or alternating, or alternate fiow and stoppage of a cur-
rent through one of the coils will produce an induced cur-
rent in the other. If the exciting or primary current fiows
through the coil having fewer turns the secondary current
from the other coil will be of higher voltage and less am-
perage, while flow of the primary current through the coil
having a larger number o^ turns will induce a current of
lower voltage and greater amperage in the other coil.
Tunnel, Armature. — The cylindrical passage formed be-
tween, the ends or pole pieces of the field magnets of a
dynamo or motor and in which the arqiature is placed.
Twenty-four Hour Bate. — See Finish Bate.
Two-Unit System. — An electric starting, lighting and igni-
tion installation in which two of the units are combined with
each other, the third being entirely separate, thus. forming
two principal parts. Such a system may use a motor-
dynamo with separate ignition device, or an ignition-dynamo
with separate starting motor.
Two-Wire System. — ^An electrical installation in which
both sides of all circuits are completed through insulated
conductors and in which no part of any circuit is carried
by the metal of the car.
Under Out. — To cut away a part of the insulation between
commutator segments so that the surface of the segments
is above that of the insulation by about ^ inch.
Vacuum Bulb. — An incandescent lamp bulb from which
almost all of the air has been exhausted and has not been
replaced with any other gas.
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ELECTRICAL WORDS AND TERMS 293
Vibrator. — An electromagnet together with its armature
and contact points used as a part of a regulator and so de-
signed and connected that the armature and movable con-
tact point vibrate at a high rate of speed so that the
circuit completed through the co'ntacts is rapidly opened and
closed.
Volt. — The unit of electrical pressure, potential or electro-
motive force. One volt pressure is produced in a. conductor
that cuts or is passed through by one hundred million lines
of magnetic force per second. One volt pressure will cause
a flow 'of one ampere through a circuit whose resistance is
one ohm.
Voltage. — The electrical pressure existing between two
points..
Voltage, Constant. — Descriptive of a form of regulation
that allows the dynamo voltage at the dynamo terminals to
rise to a predetermined maximum and then causes this volt-
age to be maintained without any great rise or fall at all
higher speeds of the dynamo.
Voltammeter. — A single measuring instrument that may
be used either as an ammeter or a voltmeter. Also an
instrument consisting of a voltmeter and a separate ammeter
in one case.
Voltmeter. — An instrument that measures difference in
electrical pressure between two points and which indicates
this difference directly in volts on a suitable scale.
Watt. — The unit of electrical power. The power delivered
by a circuit through which one ampere flows at a pressure
of one volt. The number of watts may be found by multi-
plying the number of volts by the number of amperes of a
circuit. One watt is equal to l/746th of a mechanical horse-
power. One watt is the power that must be developed to do
44^ foot-pounds of work per minute.
Watt-Hour. — A unit of electrical work equal to a power
of one watt used or applied for one hour.
Winding. — A coil composed of one or a number of turns
of a conductor around a magnetic core.
Winding, Compound. — A form of dynamo or motor field
winding consisting of a shunt and a series winding wound
on the same or separate magnet cores and acting on nne
armature.
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294 STARTING AND LIGHTING
Winding, Series. — ^In a dynamo or motor, a field winding
through which passes all of the current that flows through
the armature and brushes and in which the armature wind-
ings and field windings are in a series circuit with each
other. In a cut>out, controller or regular magnet, the wind-
ing or part of the winding through which all of the charging
current passes.
Winding, Shunt. — In a dynamo or motor-dynamo, a field
winding placed in shunt with the armature windings and
with the outside circuits and through which only a part
of the current that is generated • in the armature or that
is received from an outside source will flow. The shunt
field winding is made of much higher resistance than the
outside circuits so that no more than the necessary amount
of current required to magnetize the field magnets will pass
through the winding. In a cut-out, controller or regulator
'magnet, the winding that is connected to the positive side
of the dynamo at one end and to the negative terminal of
the dynamo at its other end which is always acted upon by
the difference in pressure or voltage between the dynamo
brushes.
Zero Center. — ^Descriptive of an electrical measuring in-
strument such as a voltmeter or ammeter in which the in-
dicating pointer may travel from the zero point toward
either end of the scale, both sides being graduated and
having the zero point at the center of the scale or nearer
to one side than to the other so that a reading of greater
value may be obtained with current flowing in one direction
than with it flowing in the other. The latter class of
instruments is not properly named "zero center" but should
be designated by the maximum readings each way, thus
''10-0-30" meaning an instrument tha^ will read to ten
amperes or volts one way and to thirty amperes or volts
in the other direction.
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INDEX
PAGE
Adjustment of cut-outs 129
of dTiiamo regulation 174
Adlake cut-out 127
regulation 164
Allis-Chalmers apparatus 267
motor-dynamos 61, 63
regulation 155
Ammeter 24, 211
attaching of 213
zero center 212
Amperage 17
constant. 269
Ampere-hour 269
meter regulation 172
Aplco regulation 161, 162
Armature ; 46
drum . . . / 46
dynamo or motor 270
reaction 270
ring 47
testing 230
Auto-Lite apparatus 241
regulation 145, 170
Base, lamp 26, 94
Battery , 23
action of 79
capacity of 77
care 88
cell 74
charge and discharge 78
charge rate of 80, 82
charging 82
discharge rate of 81
efficiency of 80
electrolyte 84
floating 81
forming of 73
grid 71
295
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296 INDEX
PAGE
Battery (continued)
paste 72
sizes of 76
specific gravity of 87
storage 70
sulphation of 80
testing 84
voltage 74
Bayonet lamp base 26, 94
Bendiz drive 189
Bijur apparatus ^ 259
Bijur manual cut-out 134
motor-dynamo control 63
starting drive 200
Bosch apparatus 261
Bosch-Eushmoore regulation 151
starting drive 194
Brush holders 54
Brush springs 55
Brushes, dynamo and motor 52
fitting 53
Bucking coil • • 271
Bucking coil regulation 151, 158
Bulbs, lamp ^2
Cables 107
Candelabra lamp base 27
Carbon resistance regulation 161
Care of battery 88
of cut-out 131
of lamps ^6
of wiring 10^
Cell, battery 74
Charge of battery 78
Charging system 11
Charging system trouble 227
Circuit ...*., • • V ?I2
breakers 116, 273
tester 230
Clatch, overrunning 191
Ceil, compensating 274
Commutating starter switches 206
Commutator ^*' lo
care ^;
troubles ^2
undercutting ^1
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INDEX 297
PAGE
Compound wound dynamo 41, 150
Condenser , 274
Conductors 108
.Consequent pole 37
Constant speed dynamo regulation 167, 170
Constant voltage regulation 138, 141
Controller 22
Current, measurement of 16
Cut-out 20, 120, 276
action of 124
adjustment 129
care C 131, 235
construction of 126
electromagnetic 120, 276
hand or manual 276
hand operated 133
location 132
manual 133
with ignition switch 136
Deaco regulation 167
Delco apparatus 248
circuit breaker 116
manual cut-out 136
motor-dynamo 63
motor-dynamo drive 179, 199
regulation 155, 166, 172
starter switch 203
Dimming bulbs 118
Dimming, lamp 117
resistance method of 119
peries-parallel system of 119
Discharge of battery 78
Disco apparatus 250
regulation 155
Double-contact lamp base 27
Double-deck unit 67, 187
Double reduction starter drive 196
Drive methods 177, 188
ratios 181
Drum armature 46
Dynamo 11
armature 46
brushes 52
compound wound ^^^i
drive systems *
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298 INDEX
PAGE
Dynamo (continued)
fields 36
four or six-pole 13
output control 137
output, rule for 35
permanent magnet 45
polarity, restoring 44
regulation 19, 137
reversed series field 43
shunt wound '. , . 38
size and capacity 34
test of 4 36
with ignition 65
Dyneto apparatus 242
manual cut-out 133
motor-dynamos 61
Ediswan lamp base 26, 94
Efficiency 277
Electrical symbols 268
Electric systems, essentials of 10
Electrical units 17
Electrolyte of battery 84, 89
Electromagnetic cut-out 120
Entz apparatus 242
manual cut-out 133
motor-dynamo drive 179
motor-dynamos 61
Field strength 40
testing ' 230
windings 36
Floating battery 81, 278
Focusing of lamps 99
Forming of storage battery 73
Fuses 113
Gramme rin^ armature . .' 47
Gray & Davis apparatus 245
regulation 150, 158, 168
Grid, battery plate 71
Ground 220
Ground return system 100
Hand operated cut-out 133
Holders, brush 54
Horsepower 280
Hydrometer 85, 280
Ignition-dynamo 65
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INDEX 299
PAGA
Indicator , 24, 216, 281
Indicating devices 24, 211
faults of 221
Induction 281
Inertia pinion drive 189
Inherent regulation 143
Insulation 108
Iron wire regulation \ 151
Jesco regulation 158
Lamp base 26, 94
Lainp bulbs 25, 92
efficiency of 93
sizes of i 94
Lamp care • 96
dimming 117
pilot 218
reflectors, cleaning of 97
socket 94
Lamps 92
focusing of 99
Leece-Neville cut-out 127
Lighting switches 110
system 25
troubles 218, 222
Magnetic gear shifting 195
switches 201
Magnetism, residual 43
Manual cut-out 133
Marker 25
Mercury well regulation 166
Miniature lamp base 27
Motor I5rush starter switch 203
Motor drive systems 178
Motor-dynamo 32, 58
reversed series field 60
starting switches 205
with external controller 62
Motor, series wound 39
starting 56
Negative polarity 286
North East apparatus 255
motor-dynamos 63
regulation 155
Ohm 284
Ohm 's Law 19, 284
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300 INDEX
PAGE
One-wire system 29, 100
Open circuit 219
Overrunning clutch - 191
Paste, battery plate 72
Permanent magnet dynamo 45
Pilot lamp 25, 218
Polarity 286
test for 45
Pole, consequent . . *. 37
Positive polarity 286
Reflectors, lamp 97
Regulation . . . ; 34
adjustment of 174
amperage 143
ampere-hour meter 172
bucking coil 151, 158
by altered field connections 167
by battery voltage 162
carbon resistance 161
characteristics of methods 139
classes of 144
by compound windings 150
constant speed 168, 170
constant voltage 137
dynamo 1^
inherent 143
iron wire ballast coil 151
line resistance 171
mercury well 166
reversed series 145
solenoid-controlled resistance ^. . 184
third-brush * • • • 147
trouble • • • 236
vibrator systems 153, 158
Relay 288
Remy apparatus • 245
ignition-dynamo ^
motor-dynamos • • • ' Jk
regulation 148, 155
Residual magnetism 43
Reversed series dynamo field 42
Reversed series regulation 145
Ring armature 47
Rushmore apparatus "ni
Rushmore regulation ^51
starting drive 1^^
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INDEX 3(ML
PAGE
Series 289
Series winding 39
Short circuit 220
Shunt 289
Shunt wound dynamo 38
Simms-Huff apparatus 264
Simms-Huff motor-dynamos 63
regulation ' I55
starting switch 208
Single-contact lamp base 27
Single-unit system 67
Socket, lamp 26, 9^:
Specific gravity 83
Splitdorf apparatus 263
Splitdorf motor-dynamo 1 59
starting switch 206
Springs, brush 55
Starting motors 56
Starting, power required 57, 182
Starting switch 200
Starting system 31
Starting trouble 218, 239
Stop-charge for regulation 162
Storage battery 70
Sulphation of battery 80
Switch, commutating .- 206
motor-dynamo starting 205
Switches, combined types 112
lighting 110
magnetic 201
starting 200
Symbols, electrical 268
Target 25
indicating 217
Terminals, wire 110
Test, armature 230
field 230
for polarity 45
of battery 84
of dynamo 36
Tester, circuit 230
Three-unit system . . , 67
Three-wire system 30, 104
Third-brush regulation 14*^
Trouble, armature 232
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802 INDEX
PAOI
Trouble (continned)
brush 228
charging system 227
circuit breaker 226
commutator 230
cut-out 235
dynamo . . • « • 228
field 232
fuse ; 225
lamp 222
lighting switch 227
permanent magnet 234
regulation 236
starting 239
starting and lighting 218
wiring • 224
.Tunnelly armature 13
Two-unit system -4 67
Two-wire system • 28, 102
Undercutting commutator 51 ,
U. S. L. apparatus 253
U. 8. L. drive method 177
motor-dynamos , 59
regulation 161
Vesta regulation ', .■ i . . . . 171
Voltage 17
Voltammeter 216
Voltmeter ....211, 214
attaching of 215
Wagner apparatus 260
Wagner motor-dynamo control 63
Ward Leonard regulation 155
Watt 18, 293
Westinghouse apparatus 253
dynamo with ignition 66
manual cut-out 134
motor-dynamo control 63
starter switches 201
starting drive , 195
Winding, compound 293
series • 294
shunt 294
Wire terminals 110
Wires 107
Wiring 27, 100
care of 109
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Farm Books
Farm Buildings, With Plans and
Descriptio^s fCloth $1.00
Farm Mechanics *Cloth 1.00
Traction Farming and Traction
Engineering *Cloth 1.50
Farm Engines and How to Run
Them Cloth 1.00
Shop Practice Books
Twentieth Century Machine Shop
Practice Cloth $2.00
Practical Mechanical Drawing Cloth 2.00
Sheet Metal Workers' Manual ... *Lea. 2.00
OxyrAcetylene Welding and Cut-
ting *Lea. 1.50
Oxy-Acetylene Welding and Cut-
ting ...*Cloth 1.00
20th Century Toolsmith and Steel-
worker Cloth 1.50
Pattern Making and Foundry
Practice Lea. 1.50
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shoeing and Wagon Making. . . Cloth 1.00
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Swingle's Handbook for Steam
Engineers and Electricians. . . .*Lea. $3.00
Steam Boilers, Construction, Care
and Operation *Lea. 1.50
Complete Examination Questions
and Answers for Marine and
Stationary Engineers *Lea. L50
Swingle's Catechism of Steam,
Gas and Electrical Engineering. *Lea. 1.50
The Steam Turbine, Its Care and
Operation Cloth 1.00
Calculation of Horse Power Made
Easy Cloth .75
Railroad Boolss
Modem Locomotive Engineering. *Lea. $3.00
Locomotive Fireman's Boiler In-
structor *Lea. 1.50
Locomotive Engine Breakdowns
and How to Repair Them *Lea. 1.50
Operation of Trains and Station
Work •Lea. 2.00
Construction and Maintenance of
Railway Roadbed and Track. . . Lea. 2.00
First, Second and Third Year
Standard Examination Ques-
tions and Answers for Locomo-
tive Firemen *Lea. 2.00
Complete Air Brake Examination
Questions and Answers *Lea. 2.00
Westinghouse Air Brake System. Cloth 2.00
New York Air Brake System Cloth 2.00
Walschaert Valve Gear Break-
downs Cloth 1.00
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Modem Carpentry. Two volumes. Cloth $2.00
Modem Carpentry. Vol. I Cloth 1.00
Modern Carpentry.. Vol. II Cloth 1.00
The Steel Square. Two volumes. . Cloth 2.00
The Steel Square. Vol. I Cloth 1.00
The Steel Square. Vol. II Cloth 1.00
A. B. C. of the Steel Square Cloth .50
Common Sense Stair Building and
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Light and Heavy Timber Framing
Made Easy Cloth 2.00
Builders' -Ajchiteetural Drawing
Self-taught Cloth 2.00
Easy Steps to Architecture Cloth 1.50
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Builders' and Contractors' Guide Cloth 1.50
Practical Bungalows and Cottages* Cloth 1.00
Low Cost American Homes * Cloth 1.00
Practical Cabinet Maker and Fur-
niture Designer Cloth 2.00
Practical Wood Carving Cloth 1.50
Home Furniture Making Cloth .60
Concretes, Cements, Mortars, Plas-
ters and Stuccos Cloth 1.50
Practical Steel Construction Cloth .75
20th Century Bricklayer and Ma-
son's Assistant Cloth 1.50
Practical Bricklaying Self-taught. Cloth 1.00
Practical Stonemasonry Cloth 1.00
Practical Up-to-date Plumbing. . . .Cloth 1.50
Hot Water Heating, Steam and
Gas Fitting Cloth 1.50
Practical Handbook for Mill-
wrights Cloth 2.00
Boat Building for Amateurs Cloth 1.00
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♦Title
\ style 1
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Art of Si&m Paintinsr
•Cloth .«3-00 1
Scene Painting and Bulletin Art. .
•Cloth
3.00
"A Show at" Sho'Cards. ........
Cloth
3.00
Strong's Book of Designs
•Lea.
3.00
Signist's Modem Book of Alpha-
bets
Cloth
1.50
Amateur Artist
Cloth
1.00
Modern Painter's Cyclopedia
Cloth
1.50
Red Book Series of Trade School
Manuals —
1. Exterior Painting, Wood,
Iron and Brick
Cloth
.60*
2. Interior Painting, Water and
Oil Colors
Cloth
.60
3. Colors
Cloth
.60
4. Graining and Marbling
Cloth
.60-
5. Carriage Painting
Cloth
.60
6. The Wood Finisher
Cloth
.60
New Hardwood Finishing
Cloth
1.00
Automobile Painting
•Cloth
1.25
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House Painting and Interior
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•Cloth 1.00
s are marked*
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Putney's Law Library
(12 volumes) Buclrrji.Tn jfifiono 1
Bookkeeping Self-taught
Cloth
1.00
Complete Courses in Bookkeeping,
Including Blank Books and
Supplies
Cloth
7.50
Elementary Chemistry Self-taught
Cloth
1.00
Picture Making for Pleasure and
Profit
Cloth
1.25
Complete Courses in Civil Service.
aoth
1.25
Felt's Parliamentary Procedure. .
Cloth
.60
McClure's Horse, Cattle and Sheep
Doctor
•eioth
1.25
Practical Lessons in Hypnotism
and Magnetism
Paper
.50
Practical Lessons in Hynotism
and Magnetism
Cloth
1 on
Chadman's Dictionary of Law. . . .
i Lea. 6.00
Modern Magician's Handbook. . . .
Cloth
1.50
White House Handbook of Ora-
tory
Cloth
1.00
Standard Cyclopedia of Receipts.
Cloth
1.25
American Star Speaker and Elo-
cutionist
Cloth
1.25
Swimming and Life Saving
Paper
.30
Words as They Look (Webster's
System of Memorising Easy
and Difficult Words)
Cloth
.50
Astrology (Were You Bom Under
a Lucky Star?)
Cloth 1.00
s are marked*
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♦Title I Style I Price
General Instruction and Reference Bod£S
Ropp's Calculator —
Style A. Large Size. . . .Moroccoline 1.25
Style B. With Flap Leather .... 1.00
Style C. Pocket Size. ...Moroccoline .60
Style D. Vest Pocket. . .Leather. ... .50
Albertus Magnus (Egyptian Se-
crets) Cloth 1.00
Sixth and Seventh Books of Moses. Cloth 1.00
Drinks as They Are Mixed Cloth .25
Drinks as They Are Mixed Lea. .50
Guide to Successful Auctioneering. Paper .25
Safe Methods of Stock Specula-
tion Cloth .50
Gypsy Witch Fortune Telling
Cards PerPack .50
. Mrs. Parker's Monologues and Flays
Monologues, Stories, Jingles and
Plays 'Cloth $1.00
New Monologues and Dialect Sto-
ries Cloth 1.00
Mary Moncure Parker's Plays —
Powder and Patches Paper .25
When Your Wife's Away Paper .25
Love Behind the Scenes Paper J.5
Mrs. Gadabout's Busy Day Paper .15
Black Art : . . . Paper .15
A Day at the Know-It-All
Woman's Club Paper .25
The Rehearsal Paper .15
The Princess Innocent Paper J.5
A Quiet Evening at Home Paper J.5
A Colonial Dream Paper J5
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SP««k«" Cloth
Paper
Comic Recitations and Readings. .$0^
$0.25
Conundrums and Riddles .50
.25
Complete Debaters' Manual £0
.25
McBride's Latest Dialogues .50
.25
Little Folk's Dialogues and Dra-
mas ••• .50
.25
Little Folk's Speaker and Enter-
tainer ^0
25
Patriotic Readings and Recitations .50
.25
Toasts and After Dinner Speeches .50
.25
Practical Ventriloquism .50
.25
Etiquette and Letter Writers
Because I Love You. • .$0.50
$0.26
Practical Etiquette and Society
Guide .50
.25
Brown's Business Letter Writer
p-nd So^iftl Forms. , ,50
.25
North's Book of Love Letters and
How to .Write Them 50
.25
Modem Quadrille Call Book and
Complete Dancing Master .50
.25
Standard Drill and Marching Book .50
.25
Card and Sleight of Hand Books
Card Sharpers— Their Tricks Ex-
posed $0.50
$0.25
The Book of Card Tricks and
Sleight of Hand .50
.25
Card Tricks— How to Do Them ... .50
.25
Tricks with Coins 50
.25
The Expert at the Card Table. ... .50
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Black Art 50
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Dream and Fortune Telling Books
Cloth Paper
The Gypsy Witch Dream Book. . .$0.50 $0.25
Original Gypsy Fortune Teller and
Dream Book .50 .25
The Mystic Circle Fortune Teller
and Dream Book. .50 .25
National Policy Players' Guide and
Dream Book 50 .25
How to Tell Fortunes by Cards. . . .50 • .25
How to Be a Clairvoyant 50 .25
Zan^ig's New Complete Palmistry. .50 .25
Dialect and Stage Jokes
Choice Dialect; Monologues and
Stage Jokes $0.50 $0.25
Dutch Dialect and Monologues. . . .50 .25
Irish Wit and Humor .50 .25
Negro Minstrels, Stump Speeches
and Monologues 50 .25
American Nights Entertainments. .50 .25
Keller's Variety Entertainments. . .50 .25
Shadow Entertainments 50 .25
Harris Complete Songster 50 .25
Business and Useful Arts
Bryant's Business Guide $0.50 $0.25
How to Make $500 Yearly Profit
with 12 Hens 50 .25
Standard Perfection Poultry Book .50 .25
A. B. C. Guide to Music 50 .25
Photography Self -Taught 50 .25
Telegraphy and How to Learn It. .50 25
Diseases of Dogs, Causes, Symp-
toms and Treatment .50 .25
Gleason's Horse Training Made
Easy .50 .25
Hodgson's Modem House Build-
ing, with Plans and Specifica-
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